Revert "w1: introduce a slave mutex for serializing IO"

This reverts commit 59d4467be4.

Turns out it was the wrong version, will apply the correct version after
this.

Reported-by: NeilBrown <neilb@suse.de>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/w1/w1.h

@@ -75,7 +75,6 @@ struct w1_slave
 	void			*family_data;
 	struct device		dev;
 	struct completion	released;
-	struct mutex		mutex;
 };
 
 typedef void (*w1_slave_found_callback)(struct w1_master *, u64);