ARM: dts: msm: Add device node for qpnp-power-on and qpnp-vibrator

qpnp-power-on supports power-on and volume-down key on PM8916.
qpnp-vibrator controls the VIB_DRV_N pin on PM8916.

Change-Id: I97cdf7289fdb8fcf3b268b16ad5204712b258339
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>