[mlir][Tosa] fix fp16/bf16 support for Clamp min/max attributes (#69192)

In TOSA MLIR dialect, fix the definition of the Clamp op to
accept fp16 & bf16 datatype for the min_fp and max_fp attributes.
Add ClampOp verifier to check attributes types compatibility.
Add related test cases in Tosa/ops.mlir.

Signed-off-by: Fabrizio Indirli <Fabrizio.Indirli@arm.com>