[GDBserver][AArch64] Remove references to aarch64-without-fpu.xml.

The GDBserver Aarch64 port includes the aarch64-without-fpu
description in the build, but doesn't actually use it anywhere.  As
Linux always requires an FPU, just remove the dead code.

gdb/gdbserver/
2013-05-28  Pedro Alves  <palves@redhat.com>

	* Makefile.in (clean): Remove reference to aarch64-without-fpu.c.
	(aarch64-without-fpu.c): Delete rule.
	* configure.srv (aarch64*-*-linux*): Remove references to
	aarch64-without-fpu.o and aarch64-without-fpu.xml.
	* linux-aarch64-low.c (init_registers_aarch64_without_fpu): Remove
	declaration.