serial: max310x: Add missing #include <linux/uaccess.h>

cris allmodconfig:

drivers/tty/serial/max310x.c: In function 'max310x_ioctl':
drivers/tty/serial/max310x.c:885:3: error: implicit declaration of function 'copy_from_user' [-Werror=implicit-function-declaration]
drivers/tty/serial/max310x.c:916:3: error: implicit declaration of function 'copy_to_user' [-Werror=implicit-function-declaration]
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/max310x.c

@@ -27,6 +27,7 @@
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
 #include <linux/spi/spi.h>
+#include <linux/uaccess.h>
 
 #define MAX310X_NAME			"max310x"
 #define MAX310X_MAJOR			204