power: qpnp-qg: add support for capacity learning and cycle counter

Capacity learning and cycle counter algorithms are supported
through fg-alg.c. Add the necessary initialization and callback
functions to qg driver to support those algorithms.

CRs-Fixed: 2225348
Change-Id: I8457da50607fc8fdbecf191bfe574d99bb2e50b4
Signed-off-by: Vamshi Krishna B V <vbv@codeaurora.org>