staging: rtl8192u: r8192U_core: fix checkpatch permission warnings

Fix the following warnings:
Symbolic permissions are not preferred. Consider using octal permissions.
Signed-off-by: Xavier Roumegue <xroumegue@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192u/r8192U_core.c

@@ -114,9 +114,9 @@ static int channels = 0x3fff;
 
 
 
-module_param(ifname, charp, S_IRUGO | S_IWUSR);
-module_param(hwwep, int, S_IRUGO | S_IWUSR);
-module_param(channels, int, S_IRUGO | S_IWUSR);
+module_param(ifname, charp, 0644);
+module_param(hwwep, int, 0644);
+module_param(channels, int, 0644);
 
 MODULE_PARM_DESC(ifname, " Net interface name, wlan%d=default");
 MODULE_PARM_DESC(hwwep, " Try to use hardware security support. ");