ac/nir: handle FRAG_RESULT_COLOR with dual src blending in ac_nir_lower_ps_early

If FRAG_RESULT_COLOR with dual_src_blend_kndex=1 is present,
FRAG_RESULT_COLOR really means FRAG_RESULT_DATA0.

Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33024>
1 file changed