Add support for new POWER ISA 3.0 instructions.

Add support for new POWER ISA 3.0 instructions.

opcodes/

	Backport from master
	2016-05-26  Peter Bergner <bergner@vnet.ibm.com>

	* ppc-opc.c (CY): New define.  Document it.
	(powerpc_opcodes) <addex[.], lwzmx, vmsumudm>: New mnemonics.

gas/
	Backport from master
	2016-05-26  Peter Bergner <bergner@vnet.ibm.com>

	* testsuite/gas/ppc/altivec3.d <vmsumudm>: Add test.
	* testsuite/gas/ppc/altivec3.s: Likewise.
	* testsuite/gas/ppc/power9.d <addex[.], lwzmx, vmsumudm>: Add tests.
	* testsuite/gas/ppc/power9.s: Likewise.