cnss2: Fix a minor discrepancy for device powering off

On device probe, cnss2 should not power off the device in api
cnss_wlan_device_init() because the device either:
  1) has already been powered down after it is enumerated by
     the pcie probe callback and its related code; or
  2) doesn't have to be powered off.

To fix this issue, add code to return directly from
cnss_wlan_device_init() without powering down the device once
cnss_bus_init() returns 0.

Change-Id: I1dd57952368471e522757cdda47bf2ac27eab112
CRs-Fixed: 3244133

cnss2/main.c

@@ -3986,6 +3986,8 @@ retry:
 		}
 		goto power_off;
 	}
+	return 0;
+
 power_off:
 	cnss_power_off_device(plat_priv);
 end: