[binutils-gdb] Don't fail in elf32_hppa_set_gp

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 55ef6584ca8466e293e9f1b310c0bf44500c11b6 ***

Author: Alan Modra <amodra@gmail.com>
Branch: master
Commit: 55ef6584ca8466e293e9f1b310c0bf44500c11b6

Don't fail in elf32_hppa_set_gp

The base bfd_link_hash_table works fine here, the only thing to watch
out for is to only set elf_gp if the output is ELF.

bfd/
	* elf32-hppa.c (elf32_hppa_set_gp): Don't require an
	hppa_link_hash_table.
ld/
	* testsuite/ld-unique/pr21529.d: Don't xfail hppa.