drm/mgag200: add in missing { } around if block

There is an if block that is missing the { } curly brackets. Add
these in.

Addresses-Coverity: ("Structurally dead code")
Fixes: 94dc57b1 ("drm/mgag200: Rewrite cursor handling")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614143911.21806-1-colin.king@canonical.com

drivers/gpu/drm/mgag200/mgag200_cursor.c

@@ -99,10 +99,11 @@ int mga_crtc_cursor_set(struct drm_crtc *crtc,
 
 	/* Pin and map up-coming buffer to write colour indices */
 	ret = drm_gem_vram_pin(pixels_next, 0);
-	if (ret)
+	if (ret) {
 		dev_err(&dev->pdev->dev,
 			"failed to pin cursor buffer: %d\n", ret);
 		goto err_drm_gem_vram_kunmap_src;
+	}
 	dst = drm_gem_vram_kmap(pixels_next, true, NULL);
 	if (IS_ERR(dst)) {
 		ret = PTR_ERR(dst);