msm: krait-regulator-pmic: account for PWM_CL register security

The PWM_CL register is secure i.e. driver has to write 0xA5 to 0XD0
register to allow updates to PWM_CL register.

Fix it.

Change-Id: I3f273627bdc137d8c10768c7d5824abe96ee8707
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>