arm: [MVE intrinsics] factorize several unary operations

Factorize vabs vcls vclz vneg vqabs vqneg vrnda vrndm vrndn vrndp vrnd
vrndx so that they use the same pattern.

This patch introduces the mve_mnemo iterator because some of the
involved intrinsics have a different name from their mnenonic: for
instance vrndq vs vrintz.

2022-09-08  Christophe Lyon  <christophe.lyon@arm.com>

	gcc/
	* config/arm/iterators.md (MVE_INT_M_UNARY, MVE_INT_UNARY)
	(MVE_FP_UNARY, MVE_FP_M_UNARY): New.
	(mve_insn): Add vabs, vcls, vclz, vneg, vqabs, vqneg, vrnda,
	vrndm, vrndn, vrndp, vrnd, vrndx.
	(isu): Add VABSQ_M_S, VCLSQ_M_S, VCLZQ_M_S, VCLZQ_M_U, VNEGQ_M_S,
	VQABSQ_M_S, VQNEGQ_M_S.
	(mve_mnemo): New.
	* config/arm/mve.md (mve_vrndq_m_f<mode>, mve_vrndxq_f<mode>)
	(mve_vrndq_f<mode>, mve_vrndpq_f<mode>, mve_vrndnq_f<mode>)
	(mve_vrndmq_f<mode>, mve_vrndaq_f<mode>): Merge into ...
	(@mve_<mve_insn>q_f<mode>): ... this.
	(mve_vnegq_f<mode>, mve_vabsq_f<mode>): Merge into ...
	(mve_v<absneg_str>q_f<mode>): ... this.
	(mve_vnegq_s<mode>, mve_vabsq_s<mode>): Merge into ...
	(mve_v<absneg_str>q_s<mode>): ... this.
	(mve_vclsq_s<mode>, mve_vqnegq_s<mode>, mve_vqabsq_s<mode>): Merge into ...
	(@mve_<mve_insn>q_<supf><mode>): ... this.
	(mve_vabsq_m_s<mode>, mve_vclsq_m_s<mode>)
	(mve_vclzq_m_<supf><mode>, mve_vnegq_m_s<mode>)
	(mve_vqabsq_m_s<mode>, mve_vqnegq_m_s<mode>): Merge into ...
	(@mve_<mve_insn>q_m_<supf><mode>): ... this.
	(mve_vabsq_m_f<mode>, mve_vnegq_m_f<mode>, mve_vrndaq_m_f<mode>)
	(mve_vrndmq_m_f<mode>, mve_vrndnq_m_f<mode>, mve_vrndpq_m_f<mode>)
	(mve_vrndxq_m_f<mode>): Merge into ...
	(@mve_<mve_insn>q_m_f<mode>): ... this.