[ARM] Fix VFP feature check

[Rot127]

ARM VFP instructions could not be disassembled if arch != armv8. This happens because of a faulty feature check. The check assumes VFP is v8 only.

This is not the case as can be checked with LLVM:

echo "0x04,0x0b,0xb7,0xee,0x10,0xfa,0xf1,0xee,0x02,0x0b,0x31,0xee,0x42,0x0b,0x31,0xee,0xc8,0x1b,0xb0,0xee" | llvm-mc-16 --triple=armv7 --mattr=+vfp3 --disassemble
	.text
	vmov.f64	d0, #1.250000e+00
	vmrs	APSR_nzcv, fpscr
	vadd.f64	d0, d1, d2
	vsub.f64	d0, d1, d2
	vabs.f64	d1, d8

[aquynh]

merged, thanks!