[binutils-gdb] x86: drop CpuRegMMX, CpuReg[XYZ]MM, and CpuRegMask

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 6e041cf4b0b00e85bee85bee98c411f16bd15747 ***

Author: Jan Beulich <jbeulich@novell.com>
Branch: master
Commit: 6e041cf4b0b00e85bee85bee98c411f16bd15747

x86: drop CpuRegMMX, CpuReg[XYZ]MM, and CpuRegMask

It's not clear to me why they had been introduced - the respective
comments in opcodes/i386-gen.c are certainly wrong: ymm<N> registers
are very well supported (and necessary) with just AVX512F.