Fix adding extra IEs in sched scan

Fix adding extra IEs in sched scan

Refactoring done in commit 46ee0427b13d64dc4695fda24f4f228c99822c11
(IEEE 802.11u: Allow Interworking and HESSID to be configured)
broke adding extra IEs in sched scan. The IEs stopped being added
to the scan params within wpa_supplicant_extra_ies() but no code
was added to add them in wpa_supplicant_req_sched_scan().
Fix this and remove unused params arg in wpa_supplicant_extra_ies().

Signed-hostap: Eyal Shapira <eyal@wizery.com>
intended-for: hostap-1