qcacmn: Avoid using freed pdev in dp_rx_bar_stats_cb

dp_reo_cmdlist_destroy frees any pending reo_cmds.
Each reo_cmd is associated with a handler which takes
reo_cmd->data as an input. This reo_cmd->data is a pdev
for dp_rx_bar_stats_cb. So validate pdev before
accessing it further.

Change-Id: I1c2d46d3e3f5ede4491500978153f501ebdeee87
CRs-Fixed: 2478910

dp/wifi3.0/dp_internal.h

@@ -861,6 +861,15 @@ uint32_t dp_pdev_tid_stats_display(void *pdev_handle,
 			enum _ol_ath_param_t param, uint32_t value, void *buff);
 #endif
 
+/**
+ * dp_check_pdev_exists() - Validate pdev before use
+ * @soc - dp soc handle
+ * @data - pdev handle
+ *
+ * Return: 0 - success/invalid - failure
+ */
+bool dp_check_pdev_exists(struct dp_soc *soc, struct dp_pdev *data);
+
 /**
  * dp_update_delay_stats() - Update delay statistics in structure
  *                              and fill min, max and avg delay