msm_serial_hs: Avoid potential unclocked access by clients

Ensure that the port configuration, data transfer activities
occur when hardware resources are available by voting for them
as the client may call shutdown and clock off asynchronously.

CRs-Fixed: 616127
Change-Id: I7ab171c2176589a54b839cfee8bb33840b55abed
Signed-off-by: Naveen Kaje <nkaje@codeaurora.org>