regulator: Add snapshot of MSM GFX LDO driver

This is a snapshot of MSM GFX LDO regulator driver for SDM660 as
of msm-4.14 'commit <90153c60c7b956e9fa> ("Merge "pinctrl-msm: Add
irq_set_wake support to msmgpio-dc irqchip")'.

Change-Id: Id13b6b601c91aa6c2c2f0e6d820a244144b60437
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>
Signed-off-by: Asha Magadi Venkateshamurthy <amagad@codeaurora.org>