hostapd: Add 11ax param only if 11ax feature is compiled

Bug: 155957464
Test: Start SAP, ensure that the 11ax error log is no longer seen.
Change-Id: I7b160d24ee21fdec5bbddf8a15bdaaa76aaa96c3
diff --git a/hostapd/hidl/1.2/hostapd.cpp b/hostapd/hidl/1.2/hostapd.cpp
index 7aa057b..537353a 100644
--- a/hostapd/hidl/1.2/hostapd.cpp
+++ b/hostapd/hidl/1.2/hostapd.cpp
@@ -375,6 +375,7 @@
 	}
 
 	std::string he_params_as_string;
+#ifdef CONFIG_IEEE80211AX
 	if (iface_params.hwModeParams.enable80211AX) {
 		he_params_as_string = StringPrintf(
 		    "ieee80211ax=1\n"
@@ -389,6 +390,7 @@
 	} else {
 		he_params_as_string = "ieee80211ax=0";
 	}
+#endif /* CONFIG_IEEE80211AX */
 
 	return StringPrintf(
 	    "interface=%s\n"