efi_loader: Add mem-mapped for fallback

When we don't have a real device/image path, such as 'bootefi hello',
construct a mem-mapped device-path.

This fixes 'bootefi hello' after devicepath refactoring.

Fixes: 95c5553ea2 ("efi_loader: refactor boot device and loaded_image handling")
Signed-off-by: Rob Clark <robdclark@gmail.com>
Acked-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/include/efi_api.h b/include/efi_api.h
index a9a6494..94c15b2 100644
--- a/include/efi_api.h
+++ b/include/efi_api.h
@@ -297,8 +297,16 @@
 } __packed;
 
 #define DEVICE_PATH_TYPE_HARDWARE_DEVICE	0x01
+#  define DEVICE_PATH_SUB_TYPE_MEMORY		0x03
 #  define DEVICE_PATH_SUB_TYPE_VENDOR		0x04
 
+struct efi_device_path_memory {
+	struct efi_device_path dp;
+	u32 memory_type;
+	u64 start_address;
+	u64 end_address;
+} __packed;
+
 struct efi_device_path_vendor {
 	struct efi_device_path dp;
 	efi_guid_t guid;