power: qpnp-fg: Define MACRO to specify MEMIF addresses

Add ability to select different MEMIF address offsets
by defining MACROs for them. The base address can
be specified through an offset array. This enables
the driver to support multiple  memory maps.

Change-Id: I774e80bac91e61f21b92374ec8108d5592692ee6
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>