power: qpnp-qg: Add CYCLE_COUNT property

Currently, CYCLE_COUNTS property shows the bucket cycle
counters as a string. Add CYCLE_COUNT property in QG that can
provide an average of all the bucket counters.

Move the helper functions that gets the cycle_counts and
cycle_count property to fg-alg.c so that it can re-used.

CRs-Fixed: 2238261
Change-Id: I18c32590c4c30e6d347284b43ac0a408614c0ffa
Signed-off-by: Vamshi Krishna B V <vbv@codeaurora.org>