ARM: dts: msm: PMI8996 enable charging

Charging was disabled for PMI8996 bring-up. Charging has been
verified on PMI8996, therefore enable it.

CRs-Fixed: 917152
Change-Id: Ib06b7e058902f40c6c50f625df146db9ed498b9a
Signed-off-by: Nicholas Troast <ntroast@codeaurora.org>