cfg80211: Pass station (extended) capability info to kernel

The information of the peer's capabilities and extended capabilities are
required for the driver to perform TDLS Peer UAPSD operations and off
channel operations. This information of the peer is passed from user space
using NL80211_CMD_SET_STATION command. This commit enhances
the function nl80211_set_station to pass the capability information of
the peer to the driver.

Similarly, there may be need for capability information for other modes,
so allow this to be provided with both add_station and change_station.

Change-Id: I1e626512a0f849ae05bbbd24c4e262d303b8f8ea
CRs-fixed: 452921

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>