efi_loader: consistent naming of protocol GUIDs

We should consistently use the same name for protocol GUIDs as defined in
the UEFI specification. Not adhering to this rule has led to duplicate
definitions for the EFI_LOADED_IMAGE_PROTOCOL_GUID.

Adjust misnamed protocol GUIDs.

Adjust the text for the graphics output protocol in the output of the
`efidebug dh` command.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/lib/efi_loader/efi_gop.c b/lib/efi_loader/efi_gop.c
index d62ce45..e003823 100644
--- a/lib/efi_loader/efi_gop.c
+++ b/lib/efi_loader/efi_gop.c
@@ -14,7 +14,7 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-static const efi_guid_t efi_gop_guid = EFI_GOP_GUID;
+static const efi_guid_t efi_gop_guid = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
 
 /**
  * struct efi_gop_obj - graphical output protocol object