md: Make mddev->chunk_size sector-based.

This patch renames the chunk_size field to chunk_sectors with the
implied change of semantics.  Since

	is_power_of_2(chunk_size) = is_power_of_2(chunk_sectors << 9)
				  = is_power_of_2(chunk_sectors)

these bits don't need an adjustment for the shift.

Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 8227ab9..5d78830 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -145,7 +145,7 @@
 	int 				external;	/* metadata is
 							 * managed externally */
 	char				metadata_type[17]; /* externally set*/
-	int				chunk_size;
+	int				chunk_sectors;
 	time_t				ctime, utime;
 	int				level, layout;
 	char				clevel[16];