[SYCL][Joint Matrix] Fix typo in matrix_combinations on PVC (#11837)
According to
https://github.com/intel/llvm/blob/sycl/sycl/doc/extensions/experimental/sycl_ext_matrix/sycl_ext_oneapi_matrix.asciidoc#intel-xmx-supported-combinations
for PVC: `matrix_type::sint8`, `matrix_type::sint8`,
`matrix_type::sint32`, `<=8`, `16`, `32` but implementation had a typo:
K == 16 instead of 32, fixed by this patch