Doc: treewide : Fix typos in DocBook/filesystem.xml

This patch fix spelling typos found in DocBook/filesystem.xml.
It is because the file was generated from comments in code,
I have to fix the comments in codes, instead of xml file.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/fs/super.c b/fs/super.c
index 7ea56de..6cd9f71 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -285,7 +285,7 @@
  *	deactivate_locked_super	-	drop an active reference to superblock
  *	@s: superblock to deactivate
  *
- *	Drops an active reference to superblock, converting it into a temprory
+ *	Drops an active reference to superblock, converting it into a temporary
  *	one if there is no other active references left.  In that case we
  *	tell fs driver to shut it down and drop the temporary reference we
  *	had just acquired.