trivial: fix then -> than typos in comments and documentation

- (better, more, bigger ...) then -> (...) than

Signed-off-by: Frederik Schwarzer <schwarzerf@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/mtd/ubi/scan.c b/drivers/mtd/ubi/scan.c
index 41d47e1..ecde202 100644
--- a/drivers/mtd/ubi/scan.c
+++ b/drivers/mtd/ubi/scan.c
@@ -478,7 +478,7 @@
 			return 0;
 		} else {
 			/*
-			 * This logical eraseblock is older then the one found
+			 * This logical eraseblock is older than the one found
 			 * previously.
 			 */
 			if (cmp_res & 4)