md: raid0 create_strip_zones(): Make two local variables sector-based.

md: raid0 create_strip_zones(): Make two local variables sector-based.

current_offset and curr_zone_offset stored the corresponding offsets
as 1K quantities. Rename them to current_start and curr_zone_start
to match the naming of struct strip_zone and store the offsets as
sector counts.

Also, add KERN_INFO to the printk() affected by this change to make
checkpatch happy.

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>