staging: rtl8723bs: use WLAN_EID_HT_CAPABILITY

Replace unique WLAN_EID_HT_CAP, _HT_CAPABILITY_IE_, and EID_HTCapability
with kernel provided WLAN_EID_HT_CAPABILITY from linux/ieee80211.h.

Signed-off-by: Ross Schmidt <ross.schm.dev@gmail.com>
Link: https://lore.kernel.org/r/20201208040733.379197-2-ross.schm.dev@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>