ARM: dts: msm: Add modem PIL node for sdxprairie

Add modem PIL device tree node for bringing the core out of
reset, shutdown & other SSR related functionalities.

Change-Id: Iaf0080f6e2d939a378753211ca80a2e3a2f1d3a5
Signed-off-by: Raghavendra Rao Ananta <rananta@codeaurora.org>