Finalize the support for building WebRTC library for iOS with bitcode

webrtc/build/webrtc.gni

Index: webrtc/build/webrtc.gni
diff --git a/webrtc/build/webrtc.gni b/webrtc/build/webrtc.gni
index 8a460f5d7ecc457a97a9e43b94c80baa305e048f..dfc1eac1c281b54ae083ca5e59d7b9c74598ecd2 100644
--- a/webrtc/build/webrtc.gni
+++ b/webrtc/build/webrtc.gni
@@ -192,10 +192,6 @@ rtc_common_configs = [ webrtc_root + ":common_config" ]
 # depending on the target having this config.
 rtc_common_inherited_config = webrtc_root + ":common_inherited_config"
 
-if (is_ios) {
-  rtc_common_configs += [ webrtc_root + "/build/ios:rtc_ios_common_config" ]
-}
-
 # Common configs to remove or add in all rtc targets.
 rtc_remove_configs = []
 rtc_add_configs = rtc_common_configs