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_net.c b/lib/efi_loader/efi_net.c
index c7d9da8..e0e222a 100644
--- a/lib/efi_loader/efi_net.c
+++ b/lib/efi_loader/efi_net.c
@@ -9,8 +9,8 @@
 #include <efi_loader.h>
 #include <malloc.h>
 
-static const efi_guid_t efi_net_guid = EFI_SIMPLE_NETWORK_GUID;
-static const efi_guid_t efi_pxe_guid = EFI_PXE_GUID;
+static const efi_guid_t efi_net_guid = EFI_SIMPLE_NETWORK_PROTOCOL_GUID;
+static const efi_guid_t efi_pxe_guid = EFI_PXE_BASE_CODE_PROTOCOL_GUID;
 static struct efi_pxe_packet *dhcp_ack;
 static bool new_rx_packet;
 static void *new_tx_packet;