IMSM: Add support for 4Kn sector size drives

IMSM: Add support for 4Kn sector size drives

This patch adds support for drives with 4Kn sector size
for IMSM metadata. Mixing member drives with 4kn and 512
is not allowed. Some offsets were aligned with sector size.
Internal metadata representation and all calculations
are still based on 512-byte sector sizes. This
implementation converts only sector based values
when reading/writing to drive, because they needs to be
stored in metadata according to accual member drive sector size.

Signed-off-by: Pawel Baldysiak <pawel.baldysiak@intel.com>
Signed-off-by: Tomasz Majchrzak <tomasz.majchrzak@intel.com>
Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>