wil6210: fix check for FW responsiveness

"echo" used to be called when no firmware loaded to the NIC,
this causes error output.

Probe firmware with "echo" only after it returned "ready" event.

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/wil6210/main.c

@@ -724,6 +724,8 @@ int wil_reset(struct wil6210_priv *wil, bool load_fw)
 
 		/* we just started MAC, wait for FW ready */
 		rc = wil_wait_for_fw_ready(wil);
+		if (rc == 0) /* check FW is responsive */
+			rc = wmi_echo(wil);
 	}
 
 	return rc;