[WIRELESS]: Fix config dependencies.

I accidentally ended up with a config that set NET_RADIO off,
and NET_WIRELESS_RTNETLINK on, which blew up thus..

net/built-in.o: In function `do_setlink':net/core/rtnetlink.c:479: undefined reference to `wireless_rtnetlink_set'
net/built-in.o: In function `do_getlink':net/core/rtnetlink.c:521: undefined reference to `wireless_rtnetlink_get'

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>