wifi: ath11k: remove unused scan_events from struct scan_req_params

As discussed lets remove the unused scan_events field from struct
scan_req_params. Also, as it is not needed anymore, remove the underlying union
wrapping too. No functionnal changes.

Link: https://lore.kernel.org/all/4be7d62e-cb59-462d-aac2-94e27efc22ff@quicinc.com/


Signed-off-by: Nicolas Escande <nico.escande@gmail.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20240211151036.1950292-1-nico.escande@gmail.com