Delete PowerPC macro insn support

Delete PowerPC macro insn support

Let's hope this stays dead, but it's here as a patch separate from
those that removed use of powerpc_macros just in case it needs to be
resurrected.

include/
	* opcode/ppc.h (struct powerpc_macro): Delete declaration.
	(powerpc_macros, powerpc_num_macros): Likewise..
opcodes/
	* ppc-opc.c (powerpc_macros, powerpc_num_macros): Delete.
gas/
	* config/tc-ppc.c (ppc_macro): Delete function.
	(ppc_macro_hash): Delete.
	(ppc_setup_opcodes, md_assemble): Delete macro support.