power: qpnp-fg-gen3: Expose cycle counters all at once

Currently, the user or client have to set cycle_count_id to read
cycle_count per SOC bucket. Instead of this, expose all cycle
counters at once using a string property "cycle_counts" .

Change-Id: I06847fb0401ebed91cc9355b7d214f2c7b127335
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>