efi: Check for failure when initing the app

The stub checks for failure with efi_init(). Add this for the app as well.
It is unlikely that anything can be done, but we may as well stop.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/lib/efi/efi_app.c b/lib/efi/efi_app.c
index 214cef9..32ed5a0 100644
--- a/lib/efi/efi_app.c
+++ b/lib/efi/efi_app.c
@@ -300,8 +300,11 @@
 	efi_status_t ret;
 
 	/* Set up access to EFI data structures */
-	efi_init(priv, "App", image, sys_table);
-
+	ret = efi_init(priv, "App", image, sys_table);
+	if (ret) {
+		printf("Failed to set up U-Boot: err=%lx\n", ret);
+		return ret;
+	}
 	efi_set_priv(priv);
 
 	/*