arm: Fix vcreate definition

From the initial merge of the MVE backend, the vcreate
intrinsic has had the vector lanes mixed up, compared
to the intended (as per the ACLE) definition. This is
also a discrepancy with clang:
https://godbolt.org/z/4n93e5aqj

This patches simply switches the operands around and
makes the tests more specific on the input registers
(I do not touch the output Q regs as they vary based
on softfp/hardfp or the input registers when the input
is a constant, since, in that case, a single register
is loaded with a constant and then the same register is
used twice as "vmov q0[2], q0[0], r2, r2" and the reg
num might not always be guaranteed).

gcc/ChangeLog:

	* config/arm/mve.md (mve_vcvtq_n_to_f_<supf><mode>): Swap operands.
	(mve_vcreateq_f<mode>): Swap operands.

gcc/testsuite/ChangeLog:

	* gcc.target/arm/mve/intrinsics/vcreateq_f16.c: Tighten test.
	* gcc.target/arm/mve/intrinsics/vcreateq_f32.c: Tighten test.
	* gcc.target/arm/mve/intrinsics/vcreateq_s16.c: Tighten test.
	* gcc.target/arm/mve/intrinsics/vcreateq_s32.c: Tighten test.
	* gcc.target/arm/mve/intrinsics/vcreateq_s64.c: Tighten test.
	* gcc.target/arm/mve/intrinsics/vcreateq_s8.c: Tighten test.
	* gcc.target/arm/mve/intrinsics/vcreateq_u16.c: Tighten test.
	* gcc.target/arm/mve/intrinsics/vcreateq_u32.c: Tighten test.
	* gcc.target/arm/mve/intrinsics/vcreateq_u64.c: Tighten test.
	* gcc.target/arm/mve/intrinsics/vcreateq_u8.c: Tighten test.