include/grub/i386/linux.h: Include missing <grub/types.h> header

include/grub/i386/linux.h: Include missing <grub/types.h> header

This header uses types defined in <grub/types.h> but does not include it,
which leads to compile errors like the following:

In file included from ../include/grub/cpu/linux.h:19,
                 from kern/efi/sb.c:21:
../include/grub/i386/linux.h:80:3: error: unknown type name ‘grub_uint64_t’
   80 |   grub_uint64_t addr;

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>