* opencl: route `sub_group_shuffle_xor` to qcom ext when KHR ext is unavailable
KHR `sub_group_shuffle_xor` is not defined by compiler when
`cl_qcom_subgroup_shuffle` is present, causing certain FA
kernels fail to build. Define the KHR shuffle_xor using
the qcom extension.
* opencl: skip FA kernels with mixed and quant types for A7x to avoid compiler crash