In further patches, we wish to enable -wredundant-decls check as
part of warning flags by default.

Change-Id: I43410d6dbf40361a503c16d94ccf0f4cf29615b7
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>

for the i.MX8M SOCs, part of the code for gpc
and PSCI implementation can be reused and make it
common for all these SoCs. this patch extracts
the common part for reuse.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>