[mlir][tosa] Align operator descriptions with the spec

This commit aligns the operator descriptions to the v1.0
spec.

Co-authored by:
  - Peng Sun <[email protected]>

Change-Id: I4774faa861e04748d411ba99fe61fe5d28475bc4
Signed-off-by: Luke Hutton <[email protected]>

Author: lhutton1