[compiler-rt][hwasan][Fuchsia] Do not emit FindDynamicShadowStart for Fuchsia

This function is unused because fuchsia does not support a dynamic shadow.

Differential Revision: https://reviews.llvm.org/D105735

compiler-rt/lib/hwasan/hwasan_dynamic_shadow.cpp

@@ -113,6 +113,15 @@ uptr FindDynamicShadowStart(uptr shadow_size_bytes) {
 }
 
 }  // namespace __hwasan
+
+#elif SANITIZER_FUCHSIA
+
+namespace __hwasan {
+
+void InitShadowGOT() {}
+
+}  // namespace __hwasan
+
 #else
 namespace __hwasan {