Fix comments: s/granuality/granularity/

I was grepping through the code and some `grep ganularity -R .` didn't
catch what I thought. Then looking closer I saw the term "granuality"
used in only four places (in comments) and granularity in many more
places describing the same idea. Some other facts:

dictionary.com does not know such a word
define:granuality on google is not found (and pages for granuality are
mostly related to patches to the kernel)
it has not been discussed as a term on LKML, AFAICS (=Can Search)

To be consistent, I think granularity should be used everywhere.

Signed-off-by: Kalin KOZHUHAROV <kalin@thinrope.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4ed7e60..1e9ebab 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -864,7 +864,7 @@
 	 */
 	struct mutex s_vfs_rename_mutex;	/* Kludge */
 
-	/* Granuality of c/m/atime in ns.
+	/* Granularity of c/m/atime in ns.
 	   Cannot be worse than a second */
 	u32		   s_time_gran;
 };