mei: fix return value on disconnection

BugLink: http://bugs.launchpad.net/bugs/1650601

commit 2d4d5481 upstream.

Correct errno on client disconnection is -ENODEV not -EBUSY
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

drivers/misc/mei/bus.c

@@ -144,7 +144,7 @@ ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length)
 		mutex_lock(&bus->device_lock);
 
 		if (!mei_cl_is_connected(cl)) {
-			rets = -EBUSY;
+			rets = -ENODEV;
 			goto out;
 		}
 	}

drivers/misc/mei/main.c

@@ -207,7 +207,7 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
 
 		mutex_lock(&dev->device_lock);
 		if (!mei_cl_is_connected(cl)) {
-			rets = -EBUSY;
+			rets = -ENODEV;
 			goto out;
 		}
 	}