rndis_wlan: make some symbols static

sparse complains, correctly, about these:

drivers/net/wireless/rndis_wlan.c:418:21: warning: symbol 'rndis_config_ops' was not declared. Should it be static?
drivers/net/wireless/rndis_wlan.c:423:6: warning: symbol 'rndis_wiphy_privid' was not declared. Should it be static?

Fix that.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>