mhi: core: fix error handling in time synchronization function

Error handling in time synchronization function is not
appropriate as an error in disabling link level low power modes
could cause a spin lock to be unlocked without being locked.

Change-Id: I06177e587f4010b0558bf1331d3b80daf6948e53
Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>