md/bitmap: use sector_div for sector_t divisions
md/bitmap: use sector_div for sector_t divisions

neilb: modified to not corrupt ->resync_max_sectors.

sector_div usage fixed by Guoqing Jiang <gqjiang@suse.com>

Signed-off-by: Stephen Rothwell <4bf0fb350827ce8d86875e76c923a478597c3cef@canb.auug.org.au>
Signed-off-by: NeilBrown <1c00aa603bb92d594c03cff60ecf8e63b2a5bcb1@suse.de>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs