[Linalg] Disallow linalg.pooling_*max/min_unsigned ops to allow float data types

[Abhishek-Varma]

linalg.pooling_nhwc_max_unsigned and linalg.pooling_nhwc_min_unsigned ops should only allow integers.

Refer to contextual find thread and refactor solution prospect discussion.

CC: @banach-space

[llvmbot]

@llvm/issue-subscribers-mlir-linalg

Author: Abhishek Varma (Abhishek-Varma)

`linalg.pooling_nhwc_max_unsigned` and `linalg.pooling_nhwc_min_unsigned` ops should only allow integers.

Refer to contextual find thread and refactor solution prospect discussion.

CC: @banach-space