power: qpnp-qnovo5: Support configuring external FET control

As per the hardware recommendation, external FET should be
controlled through a GPIO upon charger removal. Add support for
this by allowing GPIO to be configured upon charger removal.

Change-Id: Ib171cfb5dfae10a8aa5d67067b9a77740d77eb83
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>