In further patches, we aim to enable -Wredundant-decls by default.
This rearragement of helper macros is necessary to make Coverity
tool happy as well as making sure there are no redundant function
declarations for PMF related declarations.

Also, PMF related macros were added to provide appropriate function
declarations for helper APIs which capture PSCI statistics.

Change-Id: I36273032dde8fa079ef71235ed3a4629c5bfd981
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>