ARM: dts: msm: add VOLUME_P gpio key support for SDMMAGPIE

VOLUME_P key is connected to GPIO2 of PMIC, configure the
gpio and add support of VOLUME_P key for SDMMAGPIE IDP and QRD.

Change-Id: Ifac88e456b1f760bac3346f684a6872fd9a07627
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>