Fix failures in the GAS testsuite for the ARC architecture.

Fix failures in the GAS testsuite for the ARC architecture.

gas	* config/tc-arc.c (arc_option): Sets all internal gas options when
	parsing .cpu directive.
	(declare_register_set): Declare all 64 registers.
	(md_section_align): Refactor.
	(md_pcrel_from_section): Remove assert.
	(pseudo_operand_match): Fix pseudo operand match.
	(find_reloc): Use flags filed, extend matching.
	* config/tc-arc.h (TC_VALIDATE_FIX): Don't fixup any PLT
	relocation.

testsuite	* gas/arc/bic.d: Update test.
	* gas/arc/add_s-err.s: New file.
	* gas/arc/cpu-warn1.s: Likewise.
	* gas/arc/pcl-relocs.d: Likewise.
	* gas/arc/pcl-relocs.s: Likewise.
	* gas/arc/pcrel-relocs.d: Likewise.
	* gas/arc/pcrel-relocs.s: Likewise.
	* gas/arc/pic-relocs.d: Likewise.
	* gas/arc/pic-relocs.s: Likewise.
	* gas/arc/plt-relocs.d: Likewise.
	* gas/arc/plt-relocs.s: Likewise.
	* gas/arc/pseudos.d: Likewise.
	* gas/arc/pseudos.s: Likewise.
	* gas/arc/sda-relocs.d: Likewise.
	* gas/arc/sda-relocs.s: Likewise.
	* gas/arc/sda-relocs2.d: Likewise.
	* gas/arc/sda-relocs2.s: Likewise.
	* gas/arc/tls-relocs.d: Likewise.
	* gas/arc/tls-relocs.s: Likewise.

opcode	* arc.h (arc_reloc_equiv_tab): Replace flagcode with flags[32].

opcodes	* arc-dis.c (special_flag_p): Match full mnemonic.
	* arc-opc.c (print_insn_arc): Check section size to read
	appropriate number of bytes. Fix printing.
	* arc-tbl.h: Fix instruction table. Allow clri/seti instruction without
	arguments.