pinctrl: qcom: add pinctrl driver for SLPI

Sensor Low Power Island (SLPI) has a Pin controller which can
support 14 pin configurations, add pinctrl driver to handle
pins of SLPI from APPS. The snapshot of this driver is taken
from msm-4.14 commit "e4483b491ed60".

Change-Id: Id44ccb34f23a285edf0eaccb501ba4d2296a7b87
Signed-off-by: Vivek Kumar <vivekuma@codeaurora.org>