linker: align allocated blocks to 16 bytes

C/C++ requires the result of malloc/new to be
aligned for any primitive type.

Change-Id: I715b7679e738f34b3b409993fb3ef242e1321b7f
diff --git a/linker/linker_allocator.h b/linker/linker_allocator.h
index 2adad56..c1edac4 100644
--- a/linker/linker_allocator.h
+++ b/linker/linker_allocator.h
@@ -45,7 +45,7 @@
     // and allocator_addr for small ones.
     LinkerSmallObjectAllocator* allocator_addr;
   };
-};
+} __attribute__((aligned(16)));
 
 struct small_object_page_record {
   void* page_addr;