atmel: fix wiki website url

In at76c50x-usb.c the wiki url is still the old
"wireless.kernel.org" instead of the new
"wireless.wiki.kernel.org"
Signed-off-by: Flavio Suligoi <f.suligoi@asem.it>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200605154112.16277-5-f.suligoi@asem.it

drivers/net/wireless/atmel/at76c50x-usb.c

@@ -17,7 +17,7 @@
  *
  * TODO list is at the wiki:
  *
- * http://wireless.kernel.org/en/users/Drivers/at76c50x-usb#TODO
+ * https://wireless.wiki.kernel.org/en/users/Drivers/at76c50x-usb#TODO
  */
 
 #include <linux/init.h>