AArch64: Add CMP+CSEL and CMP+CSET for cores that support it

GCC 15 added two new fusions CMP+CSEL and CMP+CSET.

This patch enables them for cores that support based on their Software
Optimization Guides and generically on Armv9-A.   Even if a core does not
support it there's no negative performance impact.

gcc/ChangeLog:

	* config/aarch64/aarch64-fusion-pairs.def (AARCH64_FUSE_NEOVERSE_BASE):
	New.
	* config/aarch64/tuning_models/neoverse512tvb.h: Use it.
	* config/aarch64/tuning_models/neoversen2.h: Use it.
	* config/aarch64/tuning_models/neoversen3.h: Use it.
	* config/aarch64/tuning_models/neoversev1.h: Use it.
	* config/aarch64/tuning_models/neoversev2.h: Use it.
	* config/aarch64/tuning_models/neoversev3.h: Use it.
	* config/aarch64/tuning_models/neoversev3ae.h: Use it.
	* config/aarch64/tuning_models/cortexx925.h: Add fusions.
	* config/aarch64/tuning_models/generic_armv9_a.h: Add fusions.