Remove __INIT_REFOK and __INITDATA_REFOK

Commit 312b1485 made __INIT_REFOK expand
into .section .section ".ref.text", "ax".  Since the assembler doesn't
tolerate stuttering in the source that broke all MIPS builds.

Since with this change Sam downgraded __INIT_REFOK to just a backward
compat thing and there being only a single use in the MIPS arch code the
best solution is to delete both of __INIT_REFOK and __INITDATA_REFOK (which
was equally broken) being unused anyway these can be deleted.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>