power: qpnp-qnovo: Enable auto FG ESR extraction in CV charging

After entering into CV mode charging, Qnovo is still enabled but no PT
is rearmed, ESR extraction is expected to be handled by FG itself in
this case. QNI would detect the CV mode charging and write value 0 to
PE_CTRL2 register, so detecting this register write and notify FG driver
to enable auto ESR extraction.

Change-Id: Iffbcbdb27a2d1a45e2f7a8aef7d933c653823c46
Signed-off-by: Fenglin Wu <fenglinw@codeaurora.org>