arc/nps400: Add new instructions

arc/nps400: Add new instructions

Add some new control instructions to the opcodes library, and a new test
for these new instructions to the assembler.  The new instructions use
an instruction flag longer than any seen before (on arc), and so the max
flag length is extended to accommodate this.

gas/ChangeLog:

	* config/tc-arc.h (MAX_FLAG_NAME_LENGTH): Increase to 7.
	* testsuite/gas/arc/nps400-2.d: New file.
	* testsuite/gas/arc/nps400-2.s: New file.

opcodes/ChangeLog:

	* arc-nps400-tbl.h: Add schd, sync, and hwschd instructions.
	* arc-opc.c (arc_flag_operands): Add new flags.
	(arc_flag_classes): Add new classes.