[GDBserver] shorten srv_amd64_linux_xmlfiles

GDBserver now is able to generate target descriptions from features, so
don't need to remember these target description files.

gdb/gdbserver:

2017-07-10  Yao Qi  <yao.qi@linaro.org>

	* configure.srv (srv_amd64_linux_xmlfiles): Remove
	i386/amd64-XXX-linux from it.
1 file changed