net: wireless: bcmdhd: Send all pno scans' results

Remove ptr clearance so as to allow sched scan results as
long as supplicant doesnt issue stop.
Protect access to the sched_scan_req ptr.

Bug: 25394415

Change-Id: I381d586a2fb0a42462855e7aa80fe0d7ed723ce1
Signed-off-by: Ashwin <ashwin.bhat@broadcom.com>