nir: Generalize nir_intrinsic_vote_eq

nir: Generalize nir_intrinsic_vote_eq

The SPIR-V extension wants us to be able to do an AllEqual on any vector
or scalar type.  This has two implications:

 1) We need to be able to handle vectors so we switch the vote_eq
    intrinsics to be vectorized intrinsics.

 2) We need to handle floats which have different behavior with respect
    to +-0, NaN, etc. than the integer variant so we need two variants.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>