Set default scan IEs to the driver (QCA vendor extension)

Set default scan IEs to the driver (QCA vendor extension)

This makes wpa_supplicant set default scan IEs to the driver (if the
vendor command is supported). The driver can use these IEs in the scan
requests initiated by the driver itself. Also the driver can merge these
IEs into further scan requests that it receives, in case if the scan
request doesn't carry any of the IEs sent in this command.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>