hw/s390x/ioinst: Fix alignment problem in struct SubchDev

hw/s390x/ioinst: Fix alignment problem in struct SubchDev

struct SubchDev embeds several other structures which are marked with
QEMU_PACKED. This causes the compiler to not care for proper alignment
of these structures. When we later pass around pointers to the unaligned
struct members during migration, this causes problems on host architectures
like Sparc that can not do unaligned memory access.

Most of the structs in ioinst.h are naturally aligned, so we can fix
most of the problem by removing the QEMU_PACKED statements (and use
QEMU_BUILD_BUG_MSG() statements instead to make sure that there is no
padding). However, for the struct SCHIB, we have to keep the QEMU_PACKED
since the compiler adds some padding here otherwise. Move this struct
to the beginning of struct SubchDev instead to fix the alignment problem
here, too.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1538036615-32542-4-git-send-email-thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>