Allow to specify a character special device as a core file.

Allow to specify a character special device as a core file.

This enable us to use /dev/fwmem* as a core file.
e.g.
	ps -M /dev/fwmem0.0 -N kernel.debug
	dmesg -M /dev/fwmem0.0 -N kernel.debug
	gdb -k -c /dev/fwmem0.0 kernel.debug
You need to set target EUI64 in hw.firewire.fwmem.eui64_hi/lo before
opening the device. On the target arch, (PCI) bus address must be
equivalent to physical address.
(We cannot use this for sparc64 because of IOMMU.)

No objection in: -audit