drivers: cpuidle: lpm-levels: Remove ktime_get from suspend path

The sleep time for suspend is accounted as a part of suspend_prepare and
suspend wake call backs. Moreover the timekeeping framework is suspended
before suspend_enter calls, which causes a warning when called from within
the suspend_enter function.

Remove ktime_get() calls from within the lpm_suspend_enter() callbacks.

Change-Id: Ifff59b5caa387c603719d42a22559da6e97fdd9e
Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>
Signed-off-by: Srinivas Rao L <lsrao@codeaurora.org>