softpipe: update comments for max texture size

src/gallium/drivers/softpipe/sp_screen.c

@@ -82,11 +82,11 @@ softpipe_get_param(struct pipe_screen *screen, int param)
    case PIPE_CAP_TEXTURE_SHADOW_MAP:
       return 1;
    case PIPE_CAP_MAX_TEXTURE_2D_LEVELS:
-      return 13; /* max 2Kx2K */
+      return 13; /* max 4Kx4K */
    case PIPE_CAP_MAX_TEXTURE_3D_LEVELS:
       return 8;  /* max 128x128x128 */
    case PIPE_CAP_MAX_TEXTURE_CUBE_LEVELS:
-      return 13; /* max 2Kx2K */
+      return 13; /* max 4Kx4K */
    default:
       return 0;
    }