USB: mos7840: Cleanup useless header

BKL isn't anymore present into this file thus it is no necessary still include smp_lock.h.

Signed-off-by: Alessio Igor Bogani <abogani@texware.it>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/mos7840.c

diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 2fda1c0..f8424d1 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -26,7 +26,6 @@
 #include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
 #include <linux/tty.h>
 #include <linux/tty_driver.h>
 #include <linux/tty_flip.h>