efi: Rename END to EFI_DP_END

This exported symbol has a very generic name. Rename it to indicate that
it relates to EFI and device-paths.

Fix checkpatch warnings related to use of multiple assignments.

Signed-off-by: Simon Glass <sjg@chromium.org>
Suggested-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
index a2ab9003..3ef0a9e 100644
--- a/lib/efi_loader/efi_bootmgr.c
+++ b/lib/efi_loader/efi_bootmgr.c
@@ -856,7 +856,8 @@
 		lo.label = dev_name;
 		lo.attributes = LOAD_OPTION_ACTIVE;
 		lo.file_path = device_path;
-		lo.file_path_length = efi_dp_size(device_path) + sizeof(END);
+		lo.file_path_length = efi_dp_size(device_path) +
+			sizeof(EFI_DP_END);
 		/*
 		 * Set the dedicated guid to optional_data, it is used to identify
 		 * the boot option that automatically generated by the bootmenu.