pwm: Add snapshot of QTI PWM LPG driver

QTI PWM LPG driver supports configuring PWM/LPG channels on QTI
PMICs based on the client's request.

This snapshot is taken as of msm-4.14
commit 9bb584ae3a9d ("msm/sde/rotator: Add rev checks for sdmmagpie").

Change-Id: Icc3c6c7431e028aea6dd1759b8bad2e3b8eb9259
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>