PowerPC64 toc optimisation for power9

PowerPC64 toc optimisation for power9

Recognize power9 and a few other insns from older machines.  Fixes
linker complaints like "toc optimization is not supported for
0xf4090002 instruction".  0xf4090002 is stxsd v0,0(r9)

bfd/
	* elf64-ppc.c (ok_lo_toc_insn): Add r_type param.  Recognize
	lq,lfq,lxv,lxsd,lxssp,lfdp,stq,stfq,stxv,stxsd,stxssp,stfdp.
	Don't match lmd and stmd.
ld/
	* testsuite/ld-powerpc/tocopt7.s,
	* testsuite/ld-powerpc/tocopt7.out,
	* testsuite/ld-powerpc/tocopt7.d: New test.
	* testsuite/ld-powerpc/tocopt8.s,
	* testsuite/ld-powerpc/tocopt8.d: New test.
	* testsuite/ld-powerpc/powerpc.exp: Run them.