staging: r8188eu: change rtw_ieee80211_ht_cap type of local variables to ieee80211_ht_cap

rtw_ieee80211_ht_cap is reimplementation of the ieee80211_ht_cap.

Signed-off-by: Ivan Safonov <insafonov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>