tests/gem_media_fill: Fixup typo

Erm, there's no _em but there ia a _gem!

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/tests/gem_media_fill.c b/tests/gem_media_fill.c
index 72540a2..e3564e8 100644
--- a/tests/gem_media_fill.c
+++ b/tests/gem_media_fill.c
@@ -104,7 +104,7 @@
 	int i, j;
 
 	data.drm_fd = drm_open_driver_render(DRIVER_INTEL);
-	igt_require_em(data.drm_fd);
+	igt_require_gem(data.drm_fd);
 
 	data.devid = intel_get_drm_devid(data.drm_fd);