[MLIR][Tosa] Pass encoding through `tosa-to-linalg`

As pointed out by @Sinclair-Dee in
https://github.com/llvm/llvm-project/issues/62304, the `tosa-to-linalg`
conversion ignored the `encoding` attribute.

Also, this patch avoids an assertion error crash on unranked tensors.
Instead, the conversion now throws a "failed to legalize" error.

Fixes #62304 and fixes #63165.

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D152171