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

This reverts commit 59d4467b.

Turns out it was the wrong version, will apply the correct version after
this.
Reported-by: NNeilBrown <neilb@suse.de>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/w1/slaves/w1_bq27000.c

@@ -31,10 +31,10 @@ static int w1_bq27000_read(struct device *dev, unsigned int reg)
 	u8 val;
 	struct w1_slave *sl = container_of(dev->parent, struct w1_slave, dev);
 
-	mutex_lock(&sl->mutex);
+	mutex_lock(&sl->master->mutex);
 	w1_write_8(sl->master, HDQ_CMD_READ | reg);
 	val = w1_read_8(sl->master);
-	mutex_unlock(&sl->mutex);
+	mutex_unlock(&sl->master->mutex);
 
 	return val;
 }

drivers/w1/w1.c

@@ -686,7 +686,6 @@ static int w1_attach_slave_device(struct w1_master *dev, struct w1_reg_num *rn)
 	memcpy(&sl->reg_num, rn, sizeof(sl->reg_num));
 	atomic_set(&sl->refcnt, 0);
 	init_completion(&sl->released);
-	mutex_init(&sl->mutex);
 
 	spin_lock(&w1_flock);
 	f = w1_family_registered(rn->family);

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);