testsuite: [arm/mve] Use arm_softfp and arm_hard as needed in MVE tests

testsuite: [arm/mve] Use arm_softfp and arm_hard as needed in MVE tests

Some MVE tests explicitly test a -mfloat-abi=hard option, but we need
to check that the toolchain actually supports it (which may not be the
case for arm-linux-gnueabi* targets). We can thus remove the related
dg-skip directives.

We also make use of dg-add-options arm_v8_1m_mve_fp and arm_v8_1m_mve
instead of duplicating the corresponding options in
dg-additional-options where we keep only -mfloat-abi to override the
option selected by arm_v8_1m_mve_fp.

2020-04-22  Christophe Lyon  <christophe.lyon@linaro.org>

	gcc/testsuite/
	* gcc.target/arm/mve/intrinsics/mve_fp_fpu1.c: Use arm_hard_ok
	effective target and arm_v8_1m_mve_fp options.
	* gcc.target/arm/mve/intrinsics/mve_fp_fpu2.c: Use arm_softfp_ok
	effective target and arm_v8_1m_mve_fp options.
	* gcc.target/arm/mve/intrinsics/mve_fpu1.c: Use arm_hard_ok
	effective target and arm_v8_1m_mve options.
	* gcc.target/arm/mve/intrinsics/mve_fpu2.c: Use arm_softfp_ok
	effective target and arm_v8_1m_mve options.