[PATCH] ieee80211: Fix frame control pver mask

IEEE 802.11 frame control has two bits reserved for protocol
version. IEEE80211_FCTL_VERS was not used anywhere, but I would assume
it was supposed to be a mask for the protocol field and as such, it
should be 0x0003, not 0x0002. This matches with WLAN_FC_PVER
definition in hostap.

Signed-off-by: Jouni Malinen <jkmaline@cc.hut.fi>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>