Fix typo in gn/ios.gni.

Change-Id: Ia2862680ac87976ddf2a845b958df055755ce527
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/335869
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
diff --git a/gn/ios.gni b/gn/ios.gni
index 458e37e..beaacfc 100644
--- a/gn/ios.gni
+++ b/gn/ios.gni
@@ -148,7 +148,7 @@
                                "data_sources",
                                "extra_configs",
                              ])
-      if (defined(invoker.extra_configsa)) {
+      if (defined(invoker.extra_configs)) {
         configs += invoker.extra_configs
       }
       output_name = rebase_path("$gen_path/$app_name", root_build_dir)