staging: comedi: dt9812: remove duplicated include from dt9812.c

Remove duplicated include.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/dt9812.c

@@ -42,7 +42,6 @@ for my needs.
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/init.h>
-#include <linux/module.h>
 #include <linux/uaccess.h>
 #include <linux/usb.h>