qcacmn: Fix uninitialized var ptr issue and null check for num_pscos
1.This change fixes the use of uninitialized
variable in host driver.
2.Adds NULL check for num_psocs in mlo_peer_calculate_avg_rssi to
avoid undefined behaviour.
Change-Id: Ifbfef42b5930dfe15736a75a74e81155c5f1fbce
CRs-Fixed: 3297794