glsl/nir: Fix copying vector constant values

For n_columns == 1, we have a vector which is handled by the else
case.  Fixes invalid memory access in upcoming ARB_gl_spirv tests.

Failure bisected by Arcady Goldmints-Orlov.

Fixes: 81e51b412e9 "nir: Make nir_constant a vector rather than a matrix"
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
1 file changed