power: qpnp-fg-gen3: add SOC_REPORTING_READY property

Add SOC_REPORTING_READY property which indicates when the SOC
reporting is ready from FG driver. This can be read by healthd
daemon during its start.

Change-Id: I415e322e99bacd61c4e9ac921643d87d3eec4b3e
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>