drivers: pinctrl: qcom: Add SM6150 pinctrl driver

Add initial pinctrl driver to support pin configuration with
pinctrl framework for SM6150. This driver is a snapshot of
pinctrl-sm6150.c from msm-4.14 at commit-id "69d710e4".

Change-Id: I208418d59378550f049fb905151939fc4b73480e
Signed-off-by: Shreyas K K <shrekk@codeaurora.org>