guid: Unify GUID types

There are 3 implementations of a GUID in GRUB. Replace them with
a common one, placed in types.h.

It uses the "packed" flavor of the GUID structs, the alignment attribute
is dropped, since it is not required.

Signed-off-by: Oliver Steffen <osteffen@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

grub-core/commands/efi/lsefi.c

@@ -31,7 +31,7 @@ GRUB_MOD_LICENSE ("GPLv3+");
 
 struct known_protocol
 {
-  grub_efi_guid_t guid;
+  grub_guid_t guid;
   const char *name;
 } known_protocols[] =
   {
@@ -96,7 +96,7 @@ grub_cmd_lsefi (grub_command_t cmd __attribute__ ((unused)),
       grub_efi_handle_t handle = handles[i];
       grub_efi_status_t status;
       grub_efi_uintn_t num_protocols;
-      grub_efi_packed_guid_t **protocols;
+      grub_guid_t **protocols;
       grub_efi_device_path_t *dp;
 
       grub_printf ("Handle %p\n", handle);