sysfs: Fix one more signature discrepancy between sysfs implementation and docs.

Signed-off-by: NIra Weiny <weiny2@llnl.gov>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Documentation/filesystems/sysfs.txt

@@ -4,7 +4,7 @@ sysfs - _The_ filesystem for exporting kernel objects.
 Patrick Mochel	<mochel@osdl.org>
 Mike Murphy <mamurph@cs.clemson.edu>
 
-Revised:    10 July 2010
+Revised:    15 July 2010
 Original:   10 January 2003
 
 
@@ -333,7 +333,7 @@ Structure:
 struct bus_attribute {
         struct attribute        attr;
         ssize_t (*show)(struct bus_type *, char * buf);
-        ssize_t (*store)(struct bus_type *, const char * buf);
+        ssize_t (*store)(struct bus_type *, const char * buf, size_t count);
 };
 
 Declaring: