[gn] Disable use of dng SDK in Fuchsia

These libraries aren't configured in Fuchsia and would need some GN
reworking to enable. We can wire this up in Fuchsia if/when this
capability when needed.

Change-Id: Iec2d339da07f44516592d6114563a8a4fb59d952
Reviewed-on: https://skia-review.googlesource.com/4744
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>
diff --git a/BUILD.gn b/BUILD.gn
index 20ae541..dab8918 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -32,7 +32,8 @@
   skia_vulkan_sdk = getenv("VULKAN_SDK")
 }
 declare_args() {
-  skia_use_dng_sdk = !is_win && skia_use_libjpeg_turbo && skia_use_zlib
+  skia_use_dng_sdk =
+      !is_fuchsia && !is_win && skia_use_libjpeg_turbo && skia_use_zlib
   skia_use_sfntly = skia_use_icu
 
   if (is_android) {