microblaze: properly handle relocations in resolved symbol mode

microblaze: properly handle relocations in resolved symbol mode

The default is now to use -a -p, but microblaze currently has no support
for this.

Add support for the appropriate relocations and ignore
pc-relative and got(r20)-relative relocations.

Also:
- binfmt_flat can't support GOT data-relative relocations, so error out in that case
- Only output relocations debug if the relocation was actually created
- Tidy up the non-resolved symbol mode for microblaze

Signed-off-by: Steve Bennett <steveb@workware.net.au>