arm64: zynqmp: Move helper functions below header includes

Move helper functions in psu_init files below header includes to avoid
forward declarations.

Signed-off-by: Stefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com>
Link: https://lore.kernel.org/r/20220620163650.18756-15-stefan.herbrechtsmeier-oss@weidmueller.com


Signed-off-by: Michal Simek <michal.simek@amd.com>