x86: Check invalid XMM register in AVX512 gathers

x86: Check invalid XMM register in AVX512 gathers

Extend invalid register check for AVX512 gathers to XMM register.

	PR gas/22352
	* config/tc-i386.c (check_VecOperands): Also check XMM register
	for invalid register in AVX512 gathers.
	* testsuite/gas/i386/vgather-check.s: Add tests for AVX512
	gathers with XMM register.
	* testsuite/gas/i386/x86-64-vgather-check.s: Likewise.
	* testsuite/gas/i386/vgather-check-error.l: Updated.
	* testsuite/gas/i386/vgather-check-none.d: Likewise.
	* testsuite/gas/i386/vgather-check-warn.d: Likewise.
	* testsuite/gas/i386/vgather-check-warn.e: Likewise.
	* testsuite/gas/i386/vgather-check.d: Likewise.
	* testsuite/gas/i386/x86-64-vgather-check-error.l: Likewise.
	* testsuite/gas/i386/x86-64-vgather-check-none.d: Likewise.
	* testsuite/gas/i386/x86-64-vgather-check-warn.d: Likewise.
	* testsuite/gas/i386/x86-64-vgather-check-warn.e: Likewise.
	* testsuite/gas/i386/x86-64-vgather-check.d: Likewise.