iwmc3200wifi: fix link error when CFG80211 is not selected

The patch makes iwmc3200wifi select CFG80211 instead of LIB80211.
This fixed module link error reported by Randy Dunlap
<randy.dunlap@oracle.com> when compiling iwmc3200wifi without
cfg80211 selected. WIRELESS_EXT is also selected by iwmc3200wifi.

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>