ARM: dts: msm: enable learning feedback for PMI8994/8996 FG

Capacity learning is already enabled for PMI8994/8996 to run
the battery aging algorithm. Learning feedback is needed to
run that algorithm with providing feedback across multiple
resets. Enable it.

CRs-Fixed: 968756
Change-Id: Id6596a94f125f113c919c0bea107582165da2f90
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>