Add support for V_4B so we can properly reject it.
    
    Previously parse_vector_type_for_operand was changed to allow the use of 4b
    register size for indexed lane instructions. However this had the unintended
    side effect of also allowing 4b for normal vector registers.
    
    Because this support was only partial the rest of the tool silently treated
    4b as 8b and continued. This patch adds full support for 4b so it can be
    properly distinguished from 8b and the correct errors are generated.
    
    With this patch you still can't encode any instruction which actually requires
    v<num>.4b but such instructions don't exist so to prevent needing a workaround
    in get_vreg_qualifier_from_value this was just omitted.
    
    gas/
    
    	PR gas/22529
    	* config/tc-aarch64.c (vectype_to_qualifier): Support AARCH64_OPND_QLF_V_4B.
    	* gas/testsuite/gas/aarch64/pr22529.s: New.
    	* gas/testsuite/gas/aarch64/pr22529.d: New.
    	* gas/testsuite/gas/aarch64/pr22529.l: New.
    
    include/
    
    	PR gas/22529
    	* opcode/aarch64.h (aarch64_opnd_qualifier): Add AARCH64_OPND_QLF_V_4B.
    
    opcodes/
    
    	PR gas/22529
    	* aarch64-opc.c (aarch64_opnd_qualifiers): Add 4b variant.