V4L/DVB (10317): radio-mr800: fix radio->muted and radio->stereo

Move radio->muted and radio->stereo in section where radio mutex is
locked to avoid possible race condition problems or access to memory.
Thanks to David Ellingsworth <david@identd.dyndns.org> for pointing to
this weak place in driver.
Signed-off-by: Alexey Klimov <klimov.linux@gmail.com>
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/radio/radio-mr800.c

@@ -194,10 +194,10 @@ static int amradio_start(struct amradio_device *radio)
 		return retval;
 	}
 
-	mutex_unlock(&radio->lock);
-
 	radio->muted = 0;
 
+	mutex_unlock(&radio->lock);
+
 	return retval;
 }
 
@@ -230,10 +230,10 @@ static int amradio_stop(struct amradio_device *radio)
 		return retval;
 	}
 
-	mutex_unlock(&radio->lock);
-
 	radio->muted = 1;
 
+	mutex_unlock(&radio->lock);
+
 	return retval;
 }
 
@@ -284,10 +284,10 @@ static int amradio_setfreq(struct amradio_device *radio, int freq)
 		return retval;
 	}
 
-	mutex_unlock(&radio->lock);
-
 	radio->stereo = 0;
 
+	mutex_unlock(&radio->lock);
+
 	return retval;
 }