ARM: dts: msm: Add pm8xxx rtc device for Kona

The patch adds pm8xxx rtc device to support qpnp rtc
driver for kona. 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: Iec4cfb7c81309ad6e33cd7f1ffe3b8315a874e6c
Signed-off-by: Mohit Aggarwal <maggarwa@codeaurora.org>