efi_loader: add device-path utils

Helpers to construct device-paths from devices, partitions, files, and
for parsing and manipulating device-paths.

For non-legacy devices, this will use u-boot's device-model to construct
device-paths which include bus hierarchy to construct device-paths.  For
legacy devices we still fake it, but slightly more convincingly.

Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index 0cfdd3b..e68b0dd 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -16,7 +16,7 @@
 
 obj-$(CONFIG_CMD_BOOTEFI_HELLO) += helloworld_efi.o
 obj-y += efi_image_loader.o efi_boottime.o efi_runtime.o efi_console.o
-obj-y += efi_memory.o efi_device_path_to_text.o
+obj-y += efi_memory.o efi_device_path_to_text.o efi_device_path.o
 obj-$(CONFIG_LCD) += efi_gop.o
 obj-$(CONFIG_DM_VIDEO) += efi_gop.o
 obj-$(CONFIG_PARTITIONS) += efi_disk.o