[mlir][spirv] Add missing NV prefix/suffix for coop matrix

This is in preparation for adding the KHR version of the cooperative
matrix extension, `SPV_KHR_cooperative_matrix`, that comes with
equivalent ops and type. These are not cross-extension compatible,
so it's better to add prefixes/suffixes to the Nvidia one,
`SPV_NV_cooperative_matrix`, before adding the KHR counterparts.

In near future, I plan for these two extensions to co-exist in
the SPIR-V dialect, but we may want to remove the NV one at some point.

Reviewed By: antiagainst

Differential Revision: https://reviews.llvm.org/D154799