ARC: [plat-eznps] add support for NO_HZ_FULL

Select configuration needed as NO_HZ_FULL deps.

Signed-off-by: Noam Camus <noamc@ezchip.com>
time: remove 64BIT config dep for NO_HZ_FULL

Although ARC is 32BIT I still wan't to use NO_HZ_FULL.

Signed-off-by: Noam Camus <noamc@ezchip.com>
vmstat: remove vmstat workqueue.

With NO_HZ_FULL the task of vmstattimer is annoying.

Signed-off-by: Noam Camus <noamc@ezchip.com>
ARC: add use of schedule_user

only when CONFIG_CONTEXT_TRACKING

Signed-off-by: Noam Camus <noamc@ezchip.com>
ARC: handle large offstes to st.as

It happens when NR_CPUS is big i.e. 4k

Than the task_struct is getting too big.
It is due to cpumask which become 128 Bytes

So assembly code using st.as fails while compilation.

Signed-off-by: Noam Camus <noamc@ezchip.com>
EX livelock workaround

systemc rescheules on EX insn causing livelock when both cores are doing
EX on same mem location (tasklist spinlock in this case).

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC: fix CONFIG_DEBUG_PREEMPT warning

-------------------->8-----------------------
BUG: using smp_processor_id() in preemptible [00000000] code: klogd/41
caller is __mmdrop+0x20/0xc8
CPU: 1 PID: 41 Comm: klogd Not tainted 3.11.0+ #260

Stack Trace:
  arc_unwind_core.constprop.1+0xb4/0x120
  dump_stack+0x88/0xf8
BUG: using smp_processor_id() in preemptible [00000000] code: rcS/42
caller is __mmdrop+0x20/0xc8
  debug_smp_processor_id+0xb0/0xbc
  __mmdrop+0x20/0xc8
  schedule_tail+0xa2/0x190
  ret_from_fork+0x4/0x18
CPU: 0 PID: 42 Comm: rcS Not tainted 3.11.0+ #260

Stack Trace:
  arc_unwind_core.constprop.1+0xb4/0x120
  dump_stack+0x88/0xf8
  debug_smp_processor_id+0xb0/0xbc
  __mmdrop+0x20/0xc8
  flush_old_exec+0x3c4/0x708
  load_elf_binary+0x32a/0x1174
  search_binary_handler+0xb6/0x2c4
  load_script+0x238/0x28c
  search_binary_handler+0xb6/0x2c4
-------------------->8-----------------------

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>