soc: qcom: qpnp-pbs: Add PBS driver support

The PBS driver helps the client drivers to trigger the PBS
event to execute the PBS RAM configuration as requested by the
client driver.

Change-Id: Ic5d1290ffa0b66ac7a8f68529aafcf0b871ee3e8
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>