orinoco/hermes: select CFG80211_WEXT

It makes no sense to require the user to find and enable
CFG80211_WEXT before the driver can be selected, make the
driver select the needed Kconfig symbol itself.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>