fix do_sys_open() prototype

Fix an argument name in do_sys_open()'s prototype.
Signed-off-by: Jason Uhlenkott <juhlenko@akamai.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>

include/linux/fs.h

@@ -1536,7 +1536,7 @@ static inline int break_lease(struct inode *inode, unsigned int mode)
 
 extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
 		       struct file *filp);
-extern long do_sys_open(int fdf, const char __user *filename, int flags,
+extern long do_sys_open(int dfd, const char __user *filename, int flags,
 			int mode);
 extern struct file *filp_open(const char *, int, int);
 extern struct file * dentry_open(struct dentry *, struct vfsmount *, int);