X86: Allow additional ISAs for IAMCU in assembler

X86: Allow additional ISAs for IAMCU in assembler

Originally only Pentium integer instructions are allowed for IAMCU.
This patch removes such a restriction.  For example, 387 and SSE2
instructions can be enabled by passing "-march=iamcu+sse2+387" to
assembler.

gas/

	* config/tc-i386.c (valid_iamcu_cpu_flags): Removed.
	(set_cpu_arch): Updated.
	(md_parse_option): Likewise.
	* testsuite/gas/i386/i386.exp: Run iamcu-4 and iamcu-5.  Remove
	iamcu-inval-2 and iamcu-inval-3.
	* testsuite/gas/i386/iamcu-4.d: New file.
	* testsuite/gas/i386/iamcu-4.s: Likewise.
	* testsuite/gas/i386/iamcu-5.d: Likewise.
	* testsuite/gas/i386/iamcu-5.s: Likewise.
	* testsuite/gas/i386/iamcu-inval-2.l: Removed.
	* testsuite/gas/i386/iamcu-inval-2.s: Likewise.
	* testsuite/gas/i386/iamcu-inval-3.l: Likewise.
	* testsuite/gas/i386/iamcu-inval-3.s: Likewise.

opcodes/

	* i386-gen.c (cpu_flag_init): Remove CPU_IAMCU_COMPAT_FLAGS.
	* i386-init.h: Regenerated.