slim_msm: Fix unsafe locking in msm_sat_enqueue()

msm_sat_enqueue() calls spin_lock() and msm_sat_dequeue() calls
spin_lock_irqsave(). This leads to lockdep warnings about the
same lock being taken in interrupts on and interrupts off context
which can lead to a potential deadlock.

=================================
[ INFO: inconsistent lock state ]
3.4.0+ #382 Tainted: G        W
---------------------------------
inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
kworker/u:2/94 [HC1[1]:SC0[0]:HE0:SE1] takes:
 (&(&sat->lock)->rlock){?.+...}, at: [<c0348b80>] msm_sat_enqueue+0x20/0xb0
{HARDIRQ-ON-W} state was registered at:
  [<c00bd290>] __lock_acquire+0x664/0x8d8
  [<c00bd690>] lock_acquire+0x18c/0x1e8
  [<c06989a4>] _raw_spin_lock+0x38/0x48
  [<c0348b80>] msm_sat_enqueue+0x20/0xb0
  [<c0349338>] msm_slim_rxwq+0x278/0x42c
  [<c0349580>] msm_slim_rx_msgq_thread+0x94/0x1f8
  [<c008e480>] kthread+0x90/0xa0
  [<c000f438>] kernel_thread_exit+0x0/0x8
irq event stamp: 24219
hardirqs last  enabled at (24218): [<c0699188>] _raw_spin_unlock_irqrestore+0x3c/0x68
hardirqs last disabled at (24219): [<c06993f4>] __irq_svc+0x34/0x78
softirqs last  enabled at (24129): [<c00738a8>] irq_exit+0x54/0xa8
softirqs last disabled at (24108): [<c00738a8>] irq_exit+0x54/0xa8

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&sat->lock)->rlock);
  <Interrupt>
    lock(&(&sat->lock)->rlock);

 *** DEADLOCK ***

3 locks held by kworker/u:2/94:
 #0:  ((sat->satcl.name)){.+.+.+}, at: [<c0087124>] process_one_work+0x1e8/0x648
 #1:  ((&sat->wd)){+.+.+.}, at: [<c0087124>] process_one_work+0x1e8/0x648
 #2:  (&dev->tx_lock){+.+...}, at: [<c0349cac>] msm_xfer_msg+0xb4/0x51c

stack backtrace:
[<c00151b0>] (unwind_backtrace+0x0/0x120) from [<c00b9d48>] (print_usage_bug+0x258/0x2c0)
[<c00b9d48>] (print_usage_bug+0x258/0x2c0) from [<c00ba12c>] (mark_lock+0x37c/0x68c)
[<c00ba12c>] (mark_lock+0x37c/0x68c) from [<c00bd20c>] (__lock_acquire+0x5e0/0x8d8)
[<c00bd20c>] (__lock_acquire+0x5e0/0x8d8) from [<c00bd690>] (lock_acquire+0x18c/0x1e8)
[<c00bd690>] (lock_acquire+0x18c/0x1e8) from [<c06989a4>] (_raw_spin_lock+0x38/0x48)
[<c06989a4>] (_raw_spin_lock+0x38/0x48) from [<c0348b80>] (msm_sat_enqueue+0x20/0xb0)
[<c0348b80>] (msm_sat_enqueue+0x20/0xb0) from [<c0348dc8>] (msm_slim_interrupt+0x1b8/0x4b0)
[<c0348dc8>] (msm_slim_interrupt+0x1b8/0x4b0) from [<c00d2ccc>] (handle_irq_event_percpu+0x118/0x3a4)
[<c00d2ccc>] (handle_irq_event_percpu+0x118/0x3a4) from [<c00d2f94>] (handle_irq_event+0x3c/0x5c)
[<c00d2f94>] (handle_irq_event+0x3c/0x5c) from [<c00d5c4c>] (handle_fasteoi_irq+0xd0/0x11c)
[<c00d5c4c>] (handle_fasteoi_irq+0xd0/0x11c) from [<c00d2ae4>] (generic_handle_irq+0x24/0x2c)
[<c00d2ae4>] (generic_handle_irq+0x24/0x2c) from [<c000f370>] (handle_IRQ+0x7c/0xc0)
[<c000f370>] (handle_IRQ+0x7c/0xc0) from [<c0008774>] (gic_handle_irq+0x6c/0xc4)
[<c0008774>] (gic_handle_irq+0x6c/0xc4) from [<c0699404>] (__irq_svc+0x44/0x78)
Exception stack(0xee061cd8 to 0xee061d20)
1cc0:                                                       00000001 eebda7c8
1ce0: 00000000 eebda400 20000013 c12b5430 ec96c168 c12b542c c12b5430 00000001
1d00: 20000013 ee061e14 3eb13eb1 ee061d20 c00ba520 c069918c 20000013 ffffffff
[<c0699404>] (__irq_svc+0x44/0x78) from [<c069918c>] (_raw_spin_unlock_irqrestore+0x40/0x68)
[<c069918c>] (_raw_spin_unlock_irqrestore+0x40/0x68) from [<c0279f2c>] (__debug_object_init+0x30c/0x344)
[<c0279f2c>] (__debug_object_init+0x30c/0x344) from [<c007b068>] (init_timer_on_stack_key+0x18/0x30)
[<c007b068>] (init_timer_on_stack_key+0x18/0x30) from [<c0695248>] (schedule_timeout+0x8c/0x4c0)
[<c0695248>] (schedule_timeout+0x8c/0x4c0) from [<c069768c>] (wait_for_common+0xec/0x164)
[<c069768c>] (wait_for_common+0xec/0x164) from [<c0349fc4>] (msm_xfer_msg+0x3cc/0x51c)
[<c0349fc4>] (msm_xfer_msg+0x3cc/0x51c) from [<c034a358>] (slim_sat_rxprocess+0x244/0x664)
[<c034a358>] (slim_sat_rxprocess+0x244/0x664) from [<c0087290>] (process_one_work+0x354/0x648)
[<c0087290>] (process_one_work+0x354/0x648) from [<c0089754>] (worker_thread+0x1a8/0x2a8)
[<c0089754>] (worker_thread+0x1a8/0x2a8) from [<c008e480>] (kthread+0x90/0xa0)
[<c008e480>] (kthread+0x90/0xa0) from [<c000f438>] (kernel_thread_exit+0x0/0x8)

Make this lock irqsafe as well so that this potential bug doesn't
occur.

Change-Id: Icbef6d1d749ee6ee81b079e19e57f22c38f00c68
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>