Revert "power: qpnp-fg: disable ESR measurements during sleep"

This reverts commit a2ecbfd1.

Since PBS is responsible for disabling ESR measurements when
the chip enters low power mode and enables it back when the
chip exits low power mode, it is not needed to be done from
FG driver.

Conflicts:
	drivers/power/qpnp-fg.c

Change-Id: I3cd350e76bd336b0e0ce8a51423d819df562ba3b
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>