qcacld-3.0: Add rf test mode sysfs functionality

Add support to configure rf_test_mode_enabled.

Change-Id: I6a42cb078549ecccc5f5c769b97de14fc6f1ee79
CRs-Fixed: 3581791

wlan_qcacld3_modules.bzl

@@ -1883,6 +1883,11 @@ _conditional_srcs = {
             "core/hdd/src/wlan_hdd_sysfs_roam_trigger_bitmap.c",
         ],
     },
+    "CONFIG_WLAN_SYSFS_RF_TEST_MODE": {
+        True: [
+            "core/hdd/src/wlan_hdd_sysfs_rf_test_mode.c",
+        ],
+    },
     "CONFIG_WLAN_SYSFS_DP_STATS": {
         True: [
             "core/hdd/src/wlan_hdd_sysfs_txrx_stats_console.c",