arm: MVE: Factorize vcmp_*f*

Like in the previous, we factorize the vcmp_*f* patterns to make
maintenance easier.

2021-05-10  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/
	* config/arm/iterators.md (MVE_FP_COMPARISONS): New.
	* config/arm/mve.md (mve_vcmp<mve_cmp_op>q_f<mode>)
	(mve_vcmp<mve_cmp_op>q_n_f<mode>): New, merge all vcmp_*f*
	patterns.
	(mve_vcmpeqq_f<mode>, mve_vcmpeqq_n_f<mode>, mve_vcmpgeq_f<mode>)
	(mve_vcmpgeq_n_f<mode>, mve_vcmpgtq_f<mode>)
	(mve_vcmpgtq_n_f<mode>, mve_vcmpleq_f<mode>)
	(mve_vcmpleq_n_f<mode>, mve_vcmpltq_f<mode>)
	(mve_vcmpltq_n_f<mode>, mve_vcmpneq_f<mode>)
	(mve_vcmpneq_n_f<mode>): Remove.
	* config/arm/unspecs.md (VCMPEQQ_F, VCMPEQQ_N_F, VCMPGEQ_F)
	(VCMPGEQ_N_F, VCMPGTQ_F, VCMPGTQ_N_F, VCMPLEQ_F, VCMPLEQ_N_F)
	(VCMPLTQ_F, VCMPLTQ_N_F, VCMPNEQ_F, VCMPNEQ_N_F): Remove.