msm_serial_hs: Update usage of PNOC bus scaling voting

Currently device probe fails, if PNOC bus scaling data for HSUART device
is not available. Fail device probe only if PNOC bus scaling data is
provided and usage of same fails.

- Add PNOC bus voting/unvoting in probe before accessing any HSUART
register.
- Add PNOC bus voting/unvoting in loopback debugfs entry before accessing
any HSUART register.

Change-Id: I80d70cfba90eb73982d80feae0e10bd2d67c5073
Signed-off-by: Mayank Rana <mrana@codeaurora.org>
1 file changed