ARM: dts: msm: Add qpnp rtc device for SM6150

The patch adds qpnp rtc device to support qpnp rtc
driver for sm6150. 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: I7b412dd171677932270334e04b2f406b8a85c310
Signed-off-by: Mohit Aggarwal <maggarwa@codeaurora.org>