UBIFS: minor spelling and grammar fixes

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index c3a707d..a293490 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -655,8 +655,8 @@
  * @delta: hard and soft timeouts delta (the timer expire inteval is @softlimit
  *         and @softlimit + @delta)
  * @timer: write-buffer timer
- * @no_timer: non-zero if this write-buffer does not timer
- * @need_sync: non-zero if its timer expired and needs sync
+ * @no_timer: non-zero if this write-buffer does not have a timer
+ * @need_sync: non-zero if the timer expired and the wbuf needs sync'ing
  * @next_ino: points to the next position of the following inode number
  * @inodes: stores the inode numbers of the nodes which are in wbuf
  *