Compile reloc.o with -fno-jump-tables on MIPS.

In particular, the switch statement on the type of dynamic entries
in _rtld_relocate_nonplt_self() needs to not use a jump table since
jump tables on MIPS use local GOT entries which aren't initialized
until after this loop.

Suggested by: arichardson
Reviewed by: emaste
Sponsored by: DARPA / AFRL