util: add pwetty support for big-endian RGB565

Add support for rendering the crosshairs in a buffer using the
big-endian RGB565 format.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
v5:
  - Add Reviewed-by,

v4:
  - No changes,

v3:
  - No changes,

v2:
  - New.

tests/util/pattern.c

@@ -1337,6 +1337,7 @@ static void make_pwetty(void *data, unsigned int width, unsigned int height,
 		cairo_format = CAIRO_FORMAT_ARGB32;
 		break;
 	case DRM_FORMAT_RGB565:
+	case DRM_FORMAT_RGB565 | DRM_FORMAT_BIG_ENDIAN:
 	case DRM_FORMAT_BGR565:
 		cairo_format = CAIRO_FORMAT_RGB16_565;
 		swap16 = fb_foreign_endian(format);