staging/wireless: don't build when NET etc. are not enabled

These wireless drivers in staging could be built when
CONFIG_NET=n, CONFIG_NETDEVICES=n, causing this build error:

net/wireless/wext-priv.c: In function 'ioctl_private_call':
net/wireless/wext-priv.c:206: error: implicit declaration of function 'call_commit_handler'

due to faulty selects.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>