avx512bw: use r instead of r_ for some variables
avx512bw: use r instead of r_ for some variables

The underscore at the end is supposed to indicate that it is a private
type (i.e., simde__m*_private).  There is no need to use it when the
value doesn't need to be converted.

nemequ/simde,nemequ/simde,nemequ/simde