msm: pm-8x60: Fix suspend time tracking

Calls to sched_clock() after syscore devices have been suspend
will return the same value until the syscored devices are
resumed. Furthermore, the value won't jump forward to account for
the time left in suspend so we can't use it to calculate how much
time we spent in suspend.

We could expose the hardware directly to the pm code but it's
better to use generic interfaces. Move to using the timekeeping
APIs to determine how long we were in suspend. Unfortunately, we
can't use the timekeeping APIs this early in the resume path, so
we must read the current time of day before we suspend the
timekeeping core and after we resume the timekeeping core. Move
the calls to the suspend_late() and wake() callbacks so we can
properly read the amount of suspend time.

CRs-fixed: 536881
Change-Id: I3b47511afb75926e51e82fc83929f405404fbf07
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>