radv/llvm: fix GS shaders on GFX8/9

radv/llvm: fix GS shaders on GFX8/9

6698753cdb6 switched our GS output stores to use MUBUF.

The stride doesn't matter for the ESGS descriptor (because idxen=false and
the index stride is 64), but this fixes it anyway.

This also changes ACO to use MUBUF store too, since MTBUF doesn't seem to
work correctly with an invalid data format in the descriptor.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Fixes: 6698753cdb6 ("ac/llvm: don't use tbuffer_store as a fallback for swizzled stores")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18885>