mhi: core: Log time sync only in mission mode transition

Time sync logging requires a MHI register read which can block CPU
if MHI device is in retention. This results into blocking preemption
and irq on the core read was issued, because mhi_tryset_pm_state()
is called with write_lock_irq(). Fix the issue by moving time sync
logging into mission mode transition.

Change-Id: I5f1812f080ac101777ee6ea8e659c65700575c66
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>