efi_loader: rework bootmgr/bootefi using load_image API

In the current implementation, bootefi command and EFI boot manager
don't use load_image API, instead, use more primitive and internal
functions. This will introduce duplicated code and potentially
unknown bugs as well as inconsistent behaviours.

With this patch, do_efibootmgr() and do_boot_efi() are completely
overhauled and re-implemented using load_image API.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

Use efi_root as parent handle for the loaded image.
LoadImage() should be called with BootPolicy = true by the boot manager.
Avoid duplicate free_pool().
Eliminate variable memdp which is not needed after anymore due to
"efi_loader: correctly split device path of loaded image".

Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 72897dc..601b0a2 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -1591,6 +1591,7 @@
  * @size:	size of the loaded image
  * Return:	status code
  */
+static
 efi_status_t efi_load_image_from_path(struct efi_device_path *file_path,
 				      void **buffer, efi_uintn_t *size)
 {
@@ -2656,6 +2657,7 @@
 	}
 
 	current_image = image_handle;
+	EFI_PRINT("Jumping into 0x%p\n", image_obj->entry);
 	ret = EFI_CALL(image_obj->entry(image_handle, &systab));
 
 	/*