MLD STA: Add support for SAE external authentication offload to userspace

MLD STA: Add support for SAE external authentication offload to userspace

Enable MLO for SAE authentication when the driver indicates the AP MLD
address in an external authentication request. The MAC address of the
interface on which the external authentication request received will be
used as the own MLD address.

This commit does below for enabling MLO during external SAE
authentication:
- Use MLD addresses for SAE authentication.
- Add Basic Multi-Link element with the own MLD address in SAE
  Authentication frames.
- Send SAE Authentication frames with the source address as the own MLD
  address, destination address and BSSID as the AP MLD address to the
  driver.
- Validate the MLD address indicated by the AP in SAE Authentication
  frames against the AP MLD address indicated in external authentication
  request.
- Store the PMKSA with the AP MLD address after completing SAE
  authentication.

Signed-off-by: Veerendranath Jakkam <quic_vjakkam@quicinc.com>