[PUSHED OBV] Explicitly specify common tdesc.h for use with aarch64.h

[Alan Hayward]

Previously aarch64.h did not specify which tdesc.h to include,
and automatically ended up with the arch/ version.

arch/tdesc.h has moved to common/. This caused aarch64.h to try
and pull in the gdbserver version. Not sure why this worked when
I originally tested it.

Fix pushed as obvious.

Alan.

gdb/
	* arch/aarch64.h: Use common/tdesc.h.


diff --git a/gdb/arch/aarch64.h b/gdb/arch/aarch64.h
index 1ca83114f621cc298c55673d5060965466941251..86185f596a398b8e5048b99da4128ca61c442adf 100644
--- a/gdb/arch/aarch64.h
+++ b/gdb/arch/aarch64.h
@@ -20,7 +20,7 @@
 #ifndef ARCH_AARCH64_H
 #define ARCH_AARCH64_H

-#include "tdesc.h"
+#include "common/tdesc.h"

 target_desc *aarch64_create_target_description ();