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/test/dm/Makefile b/test/dm/Makefile
index 548649f..d46552f 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -37,6 +37,7 @@
 obj-$(CONFIG_VIDEO_MIPI_DSI) += dsi_host.o
 obj-$(CONFIG_DM_DSA) += dsa.o
 obj-$(CONFIG_ECDSA_VERIFY) += ecdsa.o
+obj-$(CONFIG_EFI_MEDIA_SANDBOX) += efi_media.o
 obj-$(CONFIG_DM_ETH) += eth.o
 ifneq ($(CONFIG_EFI_PARTITION),)
 obj-$(CONFIG_FASTBOOT_FLASH_MMC) += fastboot.o