[AArch64, 5/6] Reimplement fabd intrinsics & merge rtl patterns

[AArch64, 5/6] Reimplement fabd intrinsics & merge rtl patterns

	* config/aarch64/aarch64-builtins.def (fabd): New builtins for modes
	VALLF.
	* config/aarch64/aarch64-simd.md (fabd<mode>_3): Extend modes from VDQF
	to VALLF.  Rename to "fabd<mode>3".
	"*fabd_scalar<mode>3): Delete.
	* config/aarch64/arm_neon.h (vabds_f32): Remove inline assembly.
	Use builtin.
	(vabdd_f64): Likewise.
	(vabd_f32): Likewise.
	(vabd_f64): Likewise.
	(vabdq_f32): Likewise.
	(vabdq_f64): Likewise.

From-SVN: r237204