wireless: add VHT (802.11ac) definitions

Add the VHT definitions to be used by drivers supporting it.

Change-Id: Ia301cf72940cef19767f4f485a09c9afc12ae514
CRs-fixed: 452921

Signed-off-by: Mahesh Palivela <maheshp@posedge.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
cfg80211: allow advertising VHT capabilities

Allow drivers to advertise their VHT capabilities
and export them to userspace via nl80211.

Change-Id: I2d2825a09dfddccca1bd3edacd7fc382d765bea5
CRs-fixed: 452921

Signed-off-by: Mahesh Palivela <maheshp@posedge.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
mac80211: include VHT capability IE in probe requests

Insert the VHT capability IE into probe requests.

Change-Id: I75620090969b46701f1c760baf9c6559a4a1ac2c
CRs-fixed: 452921

Signed-off-by: Mahesh Palivela <maheshp@posedge.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>