x86: Drop using extension_opcode to encode vvvv register
gas/ChangeLog:
* config/tc-i386.c (build_modrm_byte): Dropped the use of
extension_opcode to encode the vvvv register.
* testsuite/gas/i386/x86-64-sse2avx.d: Added new testcases.
* testsuite/gas/i386/x86-64-sse2avx.s: Diito.
opcodes/ChangeLog:
* i386-opc.tbl: Added DstVVVV to some extension_opcode instructions.
* i386-tbl.h: Regenerated.