[MLIR][TOSA] Fix f16/bf16 support for MaxPool2D (#69332)

Currently, the MaxPool2D operation in the TOSA MLIR dialect does not
accept half-precision Fp16 and Bf16 tensors, converse to what is stated
in the [TOSA
Specification](https://www.mlplatform.org/tosa/tosa_spec.html#_max_pool2d).

This patch fixes the verifier to accept the two datatypes for
input/output tensors, and adds related LIT test cases in Tosa/ops.mlir