Add MIPS r3 and r5 support.

This patch firstly adds support for mips32r3 mips32r5, mips64r3
and mips64r5.  Secondly it adds support for the eretnc instruction.

ChangeLog:

bfd/
	* aoutx.h (NAME (aout, machine_type)): Add mips32r3, mips64r3,
	mips32r5 and mips64r5.
	* archures.c (bfd_architecture): Likewise.
	* bfd-in2.h (bfd_architecture): Likewise.
	* cpu-mips.c (arch_info_struct): Likewise.
	* elfxx-mips.c (mips_set_isa_flags): Likewise.

gas/
	* tc-mips.c (ISA_SUPPORTS_MIPS16E): Add mips32r3, mips32r5, mips64r3
	and mips64r5.
	(ISA_HAS_64BIT_FPRS): Likewise.
	(ISA_HAS_ROR): Likewise.
	(ISA_HAS_ODD_SINGLE_FPR): Likewise.
	(ISA_HAS_MXHC1): Likewise.
	(hilo_interlocks): Likewise.
	(md_longopts): Likewise.
	(ISA_HAS_64BIT_REGS): Add mips64r3 and mips64r5.
	(ISA_HAS_DROR): Likewise.
	(options): Add OPTION_MIPS32R3, OPTION_MIPS32R5, OPTION_MIPS64R3, and
	OPTION_MIPS64R5.
	(mips_isa_rev): Add support for mips32r3, mips32r5, mips64r3 and
	mips64r5.
	(md_parse_option): Likewise.
	(s_mipsset): Likewise.
	(mips_cpu_info_table): Add entries for mips32r3, mips32r5, mips64r3
	and mips64r5.  Also change p5600 entry to be mips32r5.
	* configure.in: Add support for mips32r3, mips32r5, mips64r3 and
	mips64r5.
	* configure: Regenerate.
	* doc/c-mips.texi: Document the -mips32r3, -mips32r5, -mips64r3 and
	-mips64r5 command line options.
	* doc/as.texinfo: Likewise.

gas/testsuite/
	* gas/mips/mips.exp: Add MIPS32r5 tests.  Also add the mips32r3,
	mips32r5, mips64r3 and mips64r5 isas to the testsuite.
	* gas/mips/r5.s: New test.
	* gas/mips/r5.d: Likewise.

include/opcode/
	* mips.h (INSN_ISA_MASK): Updated.
	(INSN_ISA32R3): New define.
	(INSN_ISA32R5): New define.
	(INSN_ISA64R3): New define.
	(INSN_ISA64R5): New define.
	(INSN_ISA64, INSN_ISA64R2, INSN_ISA3_32, INSN_ISA3_32R2, INSN_ISA4_32
	INSN_ISA4_32R2, INSN_ISA5_32R2): Renumbered.
	(mips_isa_table): Add entries for mips32r3, mips32r5, mips64r3 and
	mips64r5.
	(INSN_UPTO32R3): New define.
	(INSN_UPTO32R5): New define.
	(INSN_UPTO64R3): New define.
	(INSN_UPTO64R5): New define.
	(ISA_MIPS32R3): New define.
	(ISA_MIPS32R5): New define.
	(ISA_MIPS64R3): New define.
	(ISA_MIPS64R5): New define.
	(CPU_MIPS32R3): New define.
	(CPU_MIPS32R5): New define.
	(CPU_MIPS64R3): New define.
	(CPU_MIPS64R5): New define.

opcodes/
	* mips-opc.c (mips_builtin_opcodes): Add MIPS32r5 eretnc instruction.
	(I34): New define.
	(I36): New define.
	(I66): New define.
	(I68): New define.
	* mips-dis.c (mips_arch_choices): Add mips32r3, mips32r5, mips64r3 and
	mips64r5.
	(parse_mips_dis_option): Update MSA and virtualization support to
	allow mips64r3 and mips64r5.