qcacmn: Serialize the command eSmeCommandDelStaSession

The command eSmeCommandDelStaSession issues vdev delete to
firmware. As this command eSmeCommandDelStaSession is not
serialized, this may issue delete vdev before the peers for the
vdev are deleted, resulting in fw assert. Serialization
should be brought in for this command, so that first
eSmeCommandRoam command will do
vdev_stop-->remove_peer-->vdev_down and eSmeCommandDelStaSession
will be processed which will send vdev delete.

Post the command eSmeCommandDelStaSession to the serialization
module and WMA_DEL_STA_SELF_REQ will be posted from the sme
eSmeCommandDelStaSession handler.

Change-Id: I08f5db2d5034a29cd65929d218bf97b464447077
CRs-Fixed: 2280865

umac/cmn_services/serialization/inc/wlan_serialization_api.h

@@ -168,6 +168,7 @@ enum wlan_serialization_cmd_type {
 	WLAN_SER_CMD_ENTER_UAPSD,
 	WLAN_SER_CMD_EXIT_UAPSD,
 	WLAN_SER_CMD_EXIT_WOWL,
+	WLAN_SER_CMD_DEL_STA_SESSION,
 	WLAN_SER_CMD_MAX
 };