tools: relocate-rela: add support for handling 32-bit big endian files

tools: relocate-rela: add support for handling 32-bit big endian files

Currently, a microblaze build with CONFIG_SYS_BIG_ENDIAN=y and
CONFIG_STATIC_RELA=y fails with:
tools/relocate-rela: Not supported machine type
ELF decoding failed
make[2]: *** [u-boot/Makefile:1306: u-boot-nodtb.bin] Error 1

To fix this, convert the 32-bit codepath to use the previously added
elf{16,32}_to_cpu() functions. The aarch64 codepath is left untouched.

This commit ensures that CI doesn't fail for the next patches which enable
runtime relocation by default for microblaze.

Reviewed-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Ovidiu Panait <ovpanait@gmail.com>
Link: https://lore.kernel.org/r/20230311173838.521804-3-ovpanait@gmail.com
Signed-off-by: Michal Simek <michal.simek@amd.com>