[arm] Add architectural options

This patch adds the currently supported architecture options to the
individual architectures.  For floating point and SIMD we only permit
variants that the relevant versions of the architecture permit.  We also
add short-hand versions (+fp, +simd, etc) that allows the user to
describe using floating point without having to know the precise version
of the floating point sub-architecture that that architecture requires.

In a small number of cases we need to provide more precise versions of the
floating point architecture.  In those cases we permit traditional -mfpu
style names in the architecture description.

	* arm-cpus.in (armv5e): Add options fp, vfpv2 and nofp.
	(armv5te, armv5tej): Likewise.
	(armv6, armv6j, armv6k, armv6z, armv6kz, armv6zk, armv6t2): Likewise.
	(armv7): Add options fp and vfpv3-d16.
	(armv7-a): Add options fp, simd, vfpv3, vfpv3-d16, vfpv3-d16-fp16,
	vfpv3-fp16, vfpv4, vfpv4-d16, neon, neon-vfpv3, neon-fp16, neon-vfpv4,
	nofp and nosimd.
	(armv7ve): Likewise.
	(armv7-r): Add options fp, fp.sp, idiv, nofp and noidiv.
	(armv7e-m): Add options fp, fpv5, fp.dp and nofp.
	(armv8-a): Add nocrypto option.
	(armv8.1-a, armv8.2-a): Likewise.
	(armv8-m.main): add options fp, fp.dp and nofp.

From-SVN: r249283