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/eba.c b/drivers/mtd/ubi/eba.c
index 048a606..25def34 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -717,7 +717,7 @@
  * to the real data size, although the @buf buffer has to contain the
  * alignment. In all other cases, @len has to be aligned.
  *
- * It is prohibited to write more then once to logical eraseblocks of static
+ * It is prohibited to write more than once to logical eraseblocks of static
  * volumes. This function returns zero in case of success and a negative error
  * code in case of failure.
  */