etnaviv: disable ARB_shadow

Looks like only HALT2 GPUs have support for it but that is not yet
implemented so disable ARB_shadow for now.

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Reviewed-by: Jonathan Marek <jonathan@marek.ca>
Reviewed-by: Eric Anholt <eric@anholt.net>

src/gallium/drivers/etnaviv/etnaviv_screen.c

@@ -192,6 +192,8 @@ etna_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
       return 255;
 
    /* Texturing. */
+   case PIPE_CAP_TEXTURE_SHADOW_MAP:
+      return 0;
    case PIPE_CAP_MAX_TEXTURE_2D_SIZE:
    case PIPE_CAP_MAX_TEXTURE_ARRAY_LAYERS: /* TODO: verify */
       return screen->specs.max_texture_size;