ARM: dts: msm: Add qpnp rtc device for SDM855

The patch adds qpnp rtc device to support qpnp rtc
driver for sdm855. The rtc driver supports using the
PMIC RTC peripheral to wake a device up from suspend
or to wake it up from power-off.

Change-Id: I4c9b4e6b06a6ae24a4eaf9d3b88345f24825a350
Signed-off-by: Mohit Aggarwal <maggarwa@codeaurora.org>