[ARC] Rename "class" named attributes.

[ARC] Rename "class" named attributes.

gas/
2016-05-23  Cupertino Miranda  <cmiranda@synopsys.com>

	* config/tc-arc.c (attributes_t): Renamed attribute class to
	attr_class.
	(find_opcode_match, assemble_insn, tokenize_extinsn): Changed.

opcode/
2016-05-23  Cupertino Miranda  <cmiranda@synopsys.com>

	* arc-dis.c (find_format, find_format, get_auxreg)
	(print_insn_arc): Changed.
	* arc-ext.h (INSERT_XOP): Likewise.

include/
2016-05-23  Cupertino Miranda  <cmiranda@synopsys.com>

	* opcode/arc.h (struct arc_opcode): Renamed attribute class to
	insn_class.
	(struct arc_flag_class): Renamed attribute class to flag_class.