qcacld-3.0: Avoid possible NULL soc context dereference

Soc context fetched in hdd_rx_check_qdisc_for_adapter
is not NULL validated before passing it to other APIs.

Fix is to add NULL check for soc context in
hdd_rx_check_qdisc_for_adapter.

Change-Id: Ib6a660307009e55c54eb4b3747a8efab8e370241
CRs-Fixed: 2753253