efi: Add uclass for devices provided by UEFI firmware

UCLASS_EFI_LOADER is used for devices created by applications and
drivers loaded by U-Boots UEFI implementation.

This patch provides a new uclass (UCLASS_EFI_MEDIA) to be used for devices
that provided by a UEFI firmware calling U-Boot as an EFI application.

If the two uclasses can be unified, is left to future redesign.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/drivers/block/efi-media-uclass.c b/drivers/block/efi-media-uclass.c
new file mode 100644
index 0000000..e012f6f
--- /dev/null
+++ b/drivers/block/efi-media-uclass.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Uclass for EFI media devices
+ *
+ * Copyright 2021 Google LLC
+ */
+
+#include <common.h>
+#include <dm.h>
+
+UCLASS_DRIVER(efi_media) = {
+	.id		= UCLASS_EFI_MEDIA,
+	.name		= "efi_media",
+	.flags		= DM_UC_FLAG_SEQ_ALIAS,
+};