power: qpnp-fg-gen4: Support configuring ESR calibration during discharging

Add support to configure ESR calibration or measurements done
only during discharging. This configuration works mutually
exclusive to ESR fast calibration with the required parameters
specified by the user.

Change-Id: Id9f65e373b988af6dc60b12c932d1efaa81af42c
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>