[mlir][spirv] Add definition for OpGroupNonUniformBallotBitCount (llvm#126055)

A new constraint is also added to restrict attributes values for SPIR-V
attributes. Ideally this should use `ConfinedAttr` with a custom
constraint directly on the operand, however it seems TableGen does not
allow using that with SPIR-V attributes. I suspect it is because SPIR-V
attributes do not derive from the generic MLIR attribute class -
TableGen complains about missing enum field.

Author: IgWod-IMG