[AArch64] Use new target pass registration framework for FMA steering pass

[AArch64] Use new target pass registration framework for FMA steering pass

	* config/aarch64/aarch64.c: Delete inclusion of
	cortex-a57-fma-steering.h.
	(aarch64_override_options): Delete call
	to aarch64_register_fma_steering.
	* config/aarch64/aarch64-protos.h (make_pass_fma_steering): Declare.
	* config/aarch64/cortex-a57-fma-steering.h: Delete.
	* config/aarch64/aarch64-passes.def: New file.
	* config/aarch64/cortex-a57-fma-steering.c
	(aarch64_register_fma_steering): Delete definition.
	(make_pass_fma_steering): Remove static qualifier.
	* config/aarch64/t-aarch64 (PASSES_EXTRA): New directive.
	(cortex-a57-fma-steering.o): Remove dependency on
	cortex-a57-fma-steering.h.

From-SVN: r241248