* config/tc-arm.c (do_mla): Rename to do_mlas, take second

	* config/tc-arm.c (do_mla): Rename to do_mlas, take second
	is_mls parameter; do not diagnose Rm==Rd when is_mls.
	(do_mla, do_mls, five_bit_unsigned_immediate, bfci_lsb_and_width)
	(do_bfc, do_bfi, do_bfx, do_rbit, do_mov16, do_ldsttv4): New functions.
	(insns): Add ARMv6T2 instructions:
	bfc bfi mls movw movt rbit sbfx ubfx ldrht ldrsht ldrsbt strht.
	(arm_archs): Add V6T2 variants.
testsuite:
	* gas/arm/archv6t2.d, gas/arm/archv6t2.s: New dump test.
	* gas/arm/archv6t2-bad.l, gas/arm/archv6t2-bad.l: New errors test.
	* gas/arm/arm.exp: Run them.