Add assembly.h for use in .S files.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@85263 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/arm/fixdfsivfp.S b/lib/arm/fixdfsivfp.S
index 75c322d..4178859 100644
--- a/lib/arm/fixdfsivfp.S
+++ b/lib/arm/fixdfsivfp.S
@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "../assembly.h"
 
 //
 // extern int __fixdfsivfp(double a);