target/arm: Fix SME full tile indexing

For the outer product set of insns, which take an entire matrix
tile as output, the argument is not a combined tile+column.
Therefore using get_tile_rowcol was incorrect, as we extracted
the tile number from itself.

The test case relies only on assembler support for SME, since
no release of GCC recognizes -march=armv9-a+sme yet.

Cc: qemu-stable@nongnu.org
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1620


Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230622151201.1578522-5-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: dropped now-unneeded changes to sysregs CFLAGS]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>