wifi: Update wifi_wait_for_driver_ready return status handling

Now wifi_wait_for_driver_ready can return WIFI_ERROR_UNKNOWN also
thus update return status handling.

Bug: 157090295
Test: Basic function test, SSR test
Change-Id: Iea459bc2801418b1b21d15ce1ca3da9be64a4fe3
diff --git a/wifi/1.4/default/wifi_legacy_hal.cpp b/wifi/1.4/default/wifi_legacy_hal.cpp
index 29123bf..75f22ec 100644
--- a/wifi/1.4/default/wifi_legacy_hal.cpp
+++ b/wifi/1.4/default/wifi_legacy_hal.cpp
@@ -367,8 +367,8 @@
     }
     LOG(DEBUG) << "Waiting for the driver ready";
     wifi_error status = global_func_table_.wifi_wait_for_driver_ready();
-    if (status == WIFI_ERROR_TIMED_OUT) {
-        LOG(ERROR) << "Timed out awaiting driver ready";
+    if (status == WIFI_ERROR_TIMED_OUT || status == WIFI_ERROR_UNKNOWN) {
+        LOG(ERROR) << "Failed or timed out awaiting driver ready";
         return status;
     }
     property_set(kDriverPropName, "ok");