vc4: Stop advertising support for PIPE_CAP_TWO_SIDED_COLOR.

The GL frontend is perfectly able to handle this for us.

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8601>

src/gallium/drivers/vc4/vc4_program.c

@@ -2298,9 +2298,6 @@ vc4_shader_ntq(struct vc4_context *vc4, enum qstage stage,
 
         NIR_PASS_V(c->s, nir_lower_tex, &tex_options);
 
-        if (c->fs_key && c->fs_key->light_twoside)
-                NIR_PASS_V(c->s, nir_lower_two_sided_color, true);
-
         if (c->vs_key && c->vs_key->clamp_color)
                 NIR_PASS_V(c->s, nir_lower_clamp_color_outputs);
 
@@ -2752,7 +2749,6 @@ vc4_update_compiled_fs(struct vc4_context *vc4, uint8_t prim_mode)
         }
 
         key->ubo_1_size = vc4->constbuf[PIPE_SHADER_FRAGMENT].cb[1].buffer_size;
-        key->light_twoside = vc4->rasterizer->base.light_twoside;
 
         struct vc4_compiled_shader *old_fs = vc4->prog.fs;
         vc4->prog.fs = vc4_get_compiled_shader(vc4, QSTAGE_FRAG, &key->base);

src/gallium/drivers/vc4/vc4_qir.h

@@ -330,7 +330,6 @@ struct vc4_fs_key {
         bool is_points;
         bool is_lines;
         bool point_coord_upper_left;
-        bool light_twoside;
         bool msaa;
         bool sample_coverage;
         bool sample_alpha_to_coverage;

src/gallium/drivers/vc4/vc4_screen.c

@@ -200,6 +200,7 @@ vc4_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
                 return 1;
 
         case PIPE_CAP_ALPHA_TEST:
+        case PIPE_CAP_TWO_SIDED_COLOR:
                 return 0;
 
         default: