Staging: rtl8187se/rtl8192e/rtl8192su: allow module unload

On rtl81* additions, they had its wireless stack made builtin instead of
separated modules. But try_module_get/module_put in stack were kept,
they are uneeded with the stack builtin and makes rtl81* modules
impossible to remove on a system with an rtl81* card. request_module
calls are also uneeded with stack builtin, so remove them too.

Signed-off-by: Herton Ronaldo Krzesinski <herton@mandriva.com.br>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>