rs6000.h (ASM_CPU_SPEC): Handle -mpowerpc64 and -mcpu for power5 and rs64a.

	* config/rs6000/rs6000.h (ASM_CPU_SPEC): Handle -mpowerpc64 and -mcpu
	for power5 and rs64a.  Correct condition for default.  Correct power3,
	620, 630, 7400, 7450, G4, 970 and G5 -mcpu entries.  Add -many.

From-SVN: r83086