The Coverity complains that we might overflow into a negative value when
setting linux_params.kernel_alignment to (1 << align). We can remedy
this by casting it to grub_uint32_t.
Fixes: CID 473876
Signed-off-by: Alec Brown <alec.r.brown@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>