Remove non-existing headers from openh264 sources list

openh264 sources lists referred to two non-existing headers which
prevented gn check from successfully working on that code. This
patch removes those headers from the sources list. One of them
(utils.h) does exist but with another path, and it's already included
with that path,

Change-Id: Ie0a1e7e0b48295a28e9a89651e07800a70a36154
Reviewed-on: https://chromium-review.googlesource.com/c/1298956Reviewed-by: Henrik Boström <hbos@chromium.org>
Commit-Queue: Daniel Bratell <bratell@opera.com>
Cr-Commit-Position: refs/heads/master@{#603483}

third_party/openh264/openh264_sources.gni

@@ -7,7 +7,6 @@ openh264_common_include_dirs = [
 ]
 
 openh264_common_sources = [
-  "//third_party/openh264/src/codec/common/inc/WelsCircleQueue.h",
   "//third_party/openh264/src/codec/common/inc/WelsList.h",
   "//third_party/openh264/src/codec/common/inc/WelsLock.h",
   "//third_party/openh264/src/codec/common/inc/WelsTask.h",
@@ -50,7 +49,6 @@ openh264_common_sources = [
   "//third_party/openh264/src/codec/common/src/memory_align.cpp",
   "//third_party/openh264/src/codec/common/src/sad_common.cpp",
   "//third_party/openh264/src/codec/common/src/utils.cpp",
-  "//third_party/openh264/src/codec/common/src/utils.h",
   "//third_party/openh264/src/codec/common/src/welsCodecTrace.cpp",
 ]