qcacld-3.0: Fix null pointer dereference of lim_join_req

In lim_populate_peer_rate_set(), bss description is obtained by
dereferencing the bss descriptor from session->lim_join_req.
But in LFR-3.0 roaming case, the lim_join_req will be NULL, since
roaming is south bound operation and there is no csr join request
message after roam. So this results in NULL pointer dereference
of bss_description in lim_populate_peer_rate_set() while
handling LFR-3.0 roam synch indication event.

Pass the correct bss descriptor from caller to ensure that valid
bss descriptor is passed to the lim_populate_peer_rate_set() api.

Change-Id: I3af915d5753c7aa054dc6d8766e51fd62c8314bb
CRs-Fixed: 2733807
5 files changed