rs6000: Ignore GFXOPT (and GPOPT) for choosing machine

rs6000: Ignore GFXOPT (and GPOPT) for choosing machine

The function rs6000_machine_from_flags chooses what .machine string to
used based on the rs6000_isa_flags flags.  For that it checks for each
ISA level if something for its ISA_*_MASKS is selected.

This does not work for GFXOPT and GPOPT: these are set as flags in
ISA_2_5_MASKS_SERVER, but they aren't actually new there, they just
are not selected by default for older ISAs (they were optional).

This patch makes OPTION_MASK_PPC_GFXOPT and OPTION_MASK_PPC_GPOPT not
influence the .machine selection.

	* config/rs6000/rs6000.c (rs6000_machine_from_flags): Ignore
	OPTION_MASK_PPC_GFXOPT and OPTION_MASK_PPC_GPOPT for selecting the
	.machine string.

From-SVN: r273246