Revert of Spin off just SkLazyFnPtr from 305513002.

src/ports/SkAtomics_sync.h

Index: src/ports/SkAtomics_sync.h
diff --git a/src/ports/SkAtomics_sync.h b/src/ports/SkAtomics_sync.h
index b0d17527f07f0c50271c09d9b6699423b72dd3fa..45ba63f305c5193dee30eca074123840b0811936 100644
--- a/src/ports/SkAtomics_sync.h
+++ b/src/ports/SkAtomics_sync.h
@@ -32,12 +32,6 @@
     return __sync_bool_compare_and_swap(addr, before, after);
 }
 
-static inline __attribute__((always_inline)) void* sk_atomic_cas(void** addr,
-                                                                 void* before,
-                                                                 void* after) {
-    return __sync_val_compare_and_swap(addr, before, after);
-}
-
 static inline __attribute__((always_inline)) void sk_membar_acquire__after_atomic_conditional_inc() { }
 
 #endif