New XML descriptions for ARC, old ones removed.

	* features/arc-a5-cpu.xml: Deleted.
	* features/arc-aux-registers.dtd: Likewise.
	* features/arc600-cpu.xml: Likewise.
	* features/arc700-cpu.xml: Likewise.
	* features/arc-aux-baseline.xml: Created.
	* features/arc-aux-bcr.xml: Likewise.
	* features/arc-aux-dcache.xml: Likewise.
	* features/arc-aux-dccm.xml: Likewise.
	* features/arc-aux-debug.xml: Likewise.
	* features/arc-aux-exception.xml: Likewise.
	* features/arc-aux-icache.xml: Likewise.
	* features/arc-aux-iccm.xml: Likewise.
	* features/arc-aux-iset.xml: Likewise.
	* features/arc-aux-mpu.xml: Likewise.
	* features/arc-aux-pmrr.xml: Likewise.
	* features/arc-aux-smart.xml: Likewise.
	* features/arc-aux-timer.xml: Likewise.
	* features/arc-aux-user.xml: Likewise.
	* features/arc-core.xml: Likewise.
	* features/arc-reduced-core.xml: Likewise.
	* features/arc700.xml: Likewise.