debug/gdb: remove insight

Insight seems to be very slow to follow up on mainstreram gdb.
Latest snapshots are more than 6 months old.

Moreover, I don't have time to maintain insight support in crosstool-NG;
and, because I don't use it, I am unable to find any breakage.

--- binutils/ld/ldmain.c

+++ binutils/ld/ldmain.c

@@ -273,2 +273,5 @@ main (int argc, char **argv)

   link_info.emit_hash = TRUE;

+#ifndef __mips__

+  link_info.emit_gnu_hash = TRUE;

+#endif

   link_info.callbacks = &link_callbacks;