msm_serial_hs_lite: Vote for bus bandwidth before enabling clocks

The UART bus interface clock requires the bus clock
to be on before it can be enabled. Ensure that there
is a vote for the bus before enabling the clock.

Change-Id: I6612d6df1b890a3de39f892439a9c406b9cbdbc7
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>