ARM: dts: msm: configuring PMIC MPP2 for Backlight on APQ8017

MPP2 backlight is needed for
config 8 boards (devices without PMI).
Make changes to enable the PMIC
MPP2device node for display backlight.

Change-Id: I9a1ab3c4dedfc41e6dd7bd62af9d93b6c984b478
Acked-by: Zakir Syed <zhossain@qti.qualcomm.com>
Signed-off-by: Vijay Navnath Kamble <vkambl@codeaurora.org>
Signed-off-by: Utkarsh Saxena <usaxena@codeaurora.org>