msm: Remove idle stats and cpuidle hooks

Calling RCU functions from within the RCU quiescent state is
illegal and probably a bug. The idlestats code uses an atomic
notifier called from msm_cpuidle_enter() and that atomic notifier
takes an rcu read lock. We could fix this with a raw notifier,
but this code is unused so let's just remove the code entirely.

Change-Id: I319f0eabb56a8721c19a3b2b4bc9a7f416c88384
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
msm: cpuidle: Don't disable irqs again

cpu_idle() disables irqs before calling down into the cpuidle
driver via cpuidle_idle_call(). Disabling irqs again in
msm_cpuidle_enter() is wasteful and unnecessary. It also inhibits
our ability to determine the largest irq latency when the cpu
idles for extended periods of time because the irqsoff trace is
reenabled when the irqs are disabled in msm_cpuidle_enter().

Note that we still reenable irqs before returning, as is required
by the ARM idle loop.

Change-Id: I925478d8fef88ab490959622bc68303f59cc6e79
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>