Add copyright headers to remaining gyp files.

gyp/opts.gypi

+# Copyright 2015 Google Inc.
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
 {
         'none_sources': [
             '<(skia_src_path)/opts/SkBitmapProcState_opts_none.cpp',
             '<(skia_src_path)/opts/SkBlitMask_opts_none.cpp',
             '<(skia_src_path)/opts/SkBlitRow_opts_none.cpp',
             '<(skia_src_path)/opts/SkBlurImage_opts_none.cpp',
             '<(skia_src_path)/opts/SkMorphology_opts_none.cpp',
             '<(skia_src_path)/opts/SkTextureCompression_opts_none.cpp',
             '<(skia_src_path)/opts/SkUtils_opts_none.cpp',
             '<(skia_src_path)/opts/SkXfermode_opts_none.cpp',
@@ skipping 63 matching lines @@
             '<(skia_src_path)/opts/opts_check_x86.cpp',
         ],
         'ssse3_sources': [
             '<(skia_src_path)/opts/SkBitmapProcState_opts_SSSE3.cpp',
         ],
         'sse41_sources': [
             '<(skia_src_path)/opts/SkBlurImage_opts_SSE4.cpp',
             '<(skia_src_path)/opts/SkBlitRow_opts_SSE4.cpp',
         ],
 }