Add init for RTCVideoCodecInfo without params.

Bug: webrtc:8321
Change-Id: I4daaa54513991c2a0d4fa579e21ff33e9294ba69
Reviewed-on: https://webrtc-review.googlesource.com/5021
Reviewed-by: Daniela Jovanoska Petrenko <denicija@webrtc.org>
Commit-Queue: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20101}

sdk/objc/Framework/Classes/PeerConnection/RTCVideoCodec.mm

@@ -20,6 +20,10 @@
 @synthesize name = _name;
 @synthesize parameters = _parameters;
 
+- (instancetype)initWithName:(NSString *)name {
+  return [self initWithName:name parameters:nil];
+}
+
 - (instancetype)initWithName:(NSString *)name
                   parameters:(nullable NSDictionary<NSString *, NSString *> *)parameters {
   if (self = [super init]) {