staging: dgnc: Fix checkpatch include warning

checkpatch.pl fix. Use #include <linux/uaccess.h> instead of
<asm/uaccess.h>
Signed-off-by: NKieron Browne <kieron.browne@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/dgnc/dgnc_tty.c

@@ -47,7 +47,7 @@
 #include <linux/serial_reg.h>
 #include <linux/slab.h>
 #include <linux/delay.h>	/* For udelay */
-#include <asm/uaccess.h>	/* For copy_from_user/copy_to_user */
+#include <linux/uaccess.h>	/* For copy_from_user/copy_to_user */
 #include <linux/pci.h>
 
 #include "dgnc_driver.h"