arm64: zynqmp: add tool to minimize psu_init_gpl.c files

This script transforms a pair of psu_init_gpl.c and .h files produced by
the Xilinx Vivado tool for ZynqMP into a smaller psu_init_gpl.c file that
is almost checkpatch compliant.

Based on a script by Michal Simek.

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>