rs6000: Name set<mode>_cc, and delete some old mfcr patterns

rs6000: Name set<mode>_cc, and delete some old mfcr patterns

This names the so far unnamed basic mfcr pattern "set<mode>_cc", and
it deletes all the others (only the ashift one ever was generated, and
even that one only once during a whole bootstrap+regtest, and that one
is questionable -- we don't cost that pattern correctly).

	* config/rs6000/rs6000.md (unnamed mfcr define_insn): Name this
	set<mode>_cc.
	(unnamed define_insn_and_split): Delete.
	(unnamed define_insn): Delete.
	(unnamed define_insn): Delete.
	(unnamed define_split): Delete.

From-SVN: r279127