types: Split aligned and packed guids

On ia64 alignment requirements are strict. When we pass a pointer to
UUID it needs to be at least 4-byte aligned or EFI will crash.
On the other hand in device path there is no padding for UUID, so we
need 2 types in one formor another. Make 4-byte aligned and unaligned types

The code is structured in a way to accept unaligned inputs
in most cases and supply 4-byte aligned outputs.

Efiemu case is a bit ugly because there inputs and outputs are
reversed and so we need careful casts to account for this
inversion.

Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

grub-core/kern/efi/efi.c

@@ -1039,7 +1039,7 @@ grub_efi_find_configuration_table (const grub_guid_t *target_guid)
 
   for (i = 0; i < grub_efi_system_table->num_table_entries; i++)
     {
-      grub_guid_t *guid =
+      grub_packed_guid_t *guid =
 	&grub_efi_system_table->configuration_table[i].vendor_guid;
 
       if (! grub_memcmp (guid, target_guid, sizeof (grub_guid_t)))