This patch prefixes tile slice layout with `layout` in the
assemblyFormat:
- `<vertical>` -> `layout<vertical>`
- `<horizontal>` -> `layout<horizontal>`
The reason for this change is the current format doesn't play nicely
with additional optional operands, required to support padding and
masking (#69148), as it becomes ambiguous.
This affects the the following ops:
- arm_sme.tile_load
- arm_sme.tile_store
- arm_sme.load_tile_slice
- arm_sme.store_tile_slice
d86047cb66