mwifiex: pass ieee80211_vht_cap to mwifiex_fill_vht_cap_tlv

This patch changes mwifiex_fill_vht_cap_tlv function to pass
struct ieee80211_vht_cap instead of mwifiex_ie_types_vhtcap
so that it can be used generically.

Signed-off-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>