x86: Remove the restriction for size of the mask register in AVX10

Since AVX10.1/256 will also allow 64 bit mask register, we will
remove the restriction for size of the mask register in AVX10.

gas/ChangeLog:

	* config/tc-i386.c (VSZ128, VSZ256, VSZ512): New.
	(VEX_check_encoding): Remove opcode_modifier check for vsz.
	* testsuite/gas/i386/avx10-vsz.l: Remove testcases for mask
	registers since they are not needed.
	* testsuite/gas/i386/avx10-vsz.s: Ditto.

opcodes/ChangeLog:

	* i386-gen.c: Remove Vsz.
	* i386-opc.h: Ditto.
	* i386-opc.tbl: Remove kvsz.
	* i386-tbl.h: Regenerated.