arm: Auto-vectorization for MVE: vorn

arm: Auto-vectorization for MVE: vorn

This patch enables MVE vornq instructions for auto-vectorization.  MVE
vornq insns in mve.md are modified to use ior instead of unspec
expression.

2021-02-01  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/
	* config/arm/iterators.md (supf): Remove VORNQ_S and VORNQ_U.
	(VORNQ): Remove.
	* config/arm/mve.md (mve_vornq_s<mode>): New entry for vorn
	instruction using expression ior.
	(mve_vornq_u<mode>): New expander.
	(mve_vornq_f<mode>): Use ior code instead of unspec.
	* config/arm/unspecs.md (VORNQ_S, VORNQ_U, VORNQ_F): Remove.

	gcc/testsuite/
	* gcc.target/arm/simd/mve-vorn.c: Add vorn tests.