[AArch64][5/10] ARMv8.2-A FP16 lane vector intrinsics

[AArch64][5/10] ARMv8.2-A FP16 lane vector intrinsics

gcc/
	* config/aarch64/aarch64-simd.md (*aarch64_mulx_elt_to_64v2df): Rename to
	"*aarch64_mulx_elt_from_dup<mode>".
	(*aarch64_mul3_elt<mode>): Update schedule type.
	(*aarch64_mul3_elt_from_dup<mode>): Likewise.
	(*aarch64_fma4_elt_from_dup<mode>): Likewise.
	(*aarch64_fnma4_elt_from_dup<mode>): Likewise.
	* config/aarch64/iterators.md (VMUL): Supprt half precision float modes.
	(f, fp): Support HF modes.
	* config/aarch64/arm_neon.h (vfma_lane_f16, vfmaq_lane_f16,
	vfma_laneq_f16, vfmaq_laneq_f16, vfma_n_f16, vfmaq_n_f16, vfms_lane_f16,
        vfmsq_lane_f16, vfms_laneq_f16, vfmsq_laneq_f16, vfms_n_f16,
	vfmsq_n_f16, vmul_lane_f16, vmulq_lane_f16, vmul_laneq_f16,
	vmulq_laneq_f16, vmul_n_f16, vmulq_n_f16, vmulx_lane_f16,
	vmulxq_lane_f16, vmulx_laneq_f16, vmulxq_laneq_f16): New.

From-SVN: r238719