power: qpnp-fg: Re-enable empty soc interrupt configuration

On certain circumstances, empty soc interrupt cannot fire even
with the proper configuration. Clearing the empty soc config
and setting it back again after a FG cycle (~1.5 seconds) is
the only way to trigger empty soc interrupt again. Add it.

While at it, remove some unused macros in the driver.

CRs-Fixed: 1003838
Change-Id: I5dda1b52e19eb2086543035e0d8d1998ce709d53
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>