efi: app: Support proper reset options

At present reset just exits the U-Boot app and returns to the caller.
Add support for proper warm and cold resets, with 'hot' reset preserving
the current behaviour.

Signed-off-by: Simon Glass <sjg@chromium.org>

lib/efi_client/efi_app.c

@@ -250,7 +250,17 @@ static void efi_exit(void)
 
 static int efi_sysreset_request(struct udevice *dev, enum sysreset_t type)
 {
-	efi_exit();
+	struct efi_priv *priv = efi_get_priv();
+
+	switch (type) {
+	case SYSRESET_WARM:
+		priv->run->reset_system(EFI_RESET_WARM, EFI_SUCCESS, 0, NULL);
+		break;
+	case SYSRESET_HOT:
+	default:
+		efi_exit();
+		break;
+	}
 
 	return -EINPROGRESS;
 }