imsm: don't allow disks with different sector size in one array

imsm: don't allow disks with different sector size in one array

As there is no support in IMSM for arrays including disks with different
sector sizes, don't allow to create such configuration. Also skip the
disk with unsuitable sector size when looking for spares in the same
container.

Signed-off-by: Alexey Obitotskiy <aleksey.obitotskiy@intel.com>
Signed-off-by: Tomasz Majchrzak <tomasz.majchrzak@intel.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>