aarch64_pei_vec

I know this target is just a skeleton, but let's not write out relocs
with uninitialised garbage.

	* coff-aarch64.c (SWAP_IN_RELOC_OFFSET): Define.
	(SWAP_OUT_RELOC_OFFSET): Define.

bfd/coff-aarch64.c

@@ -72,6 +72,10 @@ static reloc_howto_type pe_aarch64_std_reloc_howto[] =
 #define bfd_pe_print_pdata      NULL
 #endif
 
+/* Handle include/coff/aarch64.h external_reloc.  */
+#define SWAP_IN_RELOC_OFFSET	H_GET_32
+#define SWAP_OUT_RELOC_OFFSET	H_PUT_32
+
 /* Return TRUE if this relocation should
    appear in the output .reloc section.  */