fuchsia: Fix build

extFormatAndroidPtr is only used on Android builds. Add
ifdefs to fix non-Android builds.

TEST: fx build
Change-Id: I91fa380e964fb37b00716664e81820176c5dd4b1
diff --git a/system/vulkan_enc/ResourceTracker.cpp b/system/vulkan_enc/ResourceTracker.cpp
index 91e4b30..3487b60 100644
--- a/system/vulkan_enc/ResourceTracker.cpp
+++ b/system/vulkan_enc/ResourceTracker.cpp
@@ -5061,10 +5061,12 @@
         info.createInfo = *pCreateInfo;
         info.createInfo.pNext = nullptr;
 
+#ifdef VK_USE_PLATFORM_ANDROID_KHR
         if (extFormatAndroidPtr && extFormatAndroidPtr->externalFormat) {
             info.hasExternalFormat = true;
             info.androidFormat = extFormatAndroidPtr->externalFormat;
         }
+#endif  // VK_USE_PLATFORM_ANDROID_KHR
 
         if (supportsCreateResourcesWithRequirements()) {
             info.baseRequirementsKnown = true;