fix failure of sh reloc.h to properly detect endianness for ldso name

versions of reloc.h that rely on endian macros much include endian.h
to ensure they are available.

arch/sh/reloc.h

@@ -1,3 +1,5 @@
+#include <endian.h>
+
 #if __BYTE_ORDER == __BIG_ENDIAN
 #define ENDIAN_SUFFIX "eb"
 #else