amdgcn: switch mov insns to compact syntax

amdgcn: switch mov insns to compact syntax

The move instructions typically have many alternatives (and I'm about to add
more) so are good candidates for the new syntax.

This patch only converts the patterns where there are no significant changes to
the generated files. The other patterns can be converted another time.

gcc/ChangeLog:

	* config/gcn/gcn-valu.md (*mov<mode>): Convert to compact syntax.
	(mov<mode>_exec): Likewise.
	(mov<mode>_sgprbase): Likewise.
	* config/gcn/gcn.md (*mov<mode>_insn): Likewise.
	(*movti_insn): Likewise.