ARM: dts: msm: add PMIC power-on peripheral devices for SDM855

Add power-on peripheral devices for PM855, PM855B, and PM855L.
These devices ensure that power key and volume down key presses
can be handled.

Change-Id: I34fdd0788668a2cfe4ca6b24150ba9f42d534ccd
Signed-off-by: David Collins <collinsd@codeaurora.org>