MIPS/BFD: Fix rightshift for remaining n32 reloc howtos

Correct the rightshift amount for the R_MIPS_HIGHER, R_MIPS_HIGHEST and
R_MIPS_CALL_HI16 RELA relocation howtos, missed with commit f38e9921479a
("MIPS HI16 and LO16 reloc howtos").
1 file changed