Remove unsupported `am34-*-linux*' target triplet

Remove unsupported `am34-*-linux*' target triplet

The `am34-*-linux*' target cannot be configured for, `am34' is not a CPU
name recognized by `config.sub'.  It has never been, required code has
not been contributed to GNU config, neither before nor since the
addition of the target triplet to our configury with commit bfff16424942
("Add MN10300 linker relaxation support for symbol differences") back in
2007.  Also there is no difference in actual tool configuration between
the `am34-*-linux*' and `am33_2.0-*-linux*' targets, except from a
different executable prefix and tooldir name.

Given the above remove the target triplet from our configuration.

	bfd/
	* config.bfd: Remove `am34-*-linux*' support.

	ld/
	* configure.tgt: Remove `am34-*-linux*' support.