Add SBP-II target mode driver.

Though this is still incomplete and has some missing features such as
exclusive login and event notification, it may be enough for someone
who wants to play with it.

This driver is supposed to work with firewire(4), targ(4) of CAM(4)
and scsi_target(8) which can be found in /usr/share/example/scsi_target.
This driver doesn't require sbp(4) which implements initiator mode.

Sample configuration:

Kernel: (you can use modules as well)
device	firewire
device	scbus
device	targ
device	sbp_targ

After reboot:
# mdconfig -a -t malloc -s 10m
md0
# scsi_target 0:0:0 /dev/md0
(Assuming sbp_targ0 on scbus0)

You should find the 10MB HDD on FreeBSD/MacOS X/WinXP or whatever connected
to the target using FireWire.

Manpage is not finished yet.

sys/conf/files

@@ -416,6 +416,7 @@ dev/firewire/fwohci.c	optional firewire
 dev/firewire/fwohci_pci.c	optional firewire pci
 dev/firewire/if_fwe.c	optional fwe
 dev/firewire/sbp.c	optional sbp
+dev/firewire/sbp_targ.c	optional sbp_targ
 dev/fxp/if_fxp.c	optional fxp
 dev/gem/if_gem.c	optional gem
 dev/gem/if_gem_pci.c	optional gem pci

sys/modules/firewire/Makefile

@@ -3,6 +3,7 @@
 SUBDIR =
 SUBDIR += firewire
 SUBDIR += sbp
+SUBDIR += sbp_targ
 SUBDIR += fwe
 
 .include <bsd.subdir.mk>

sys/modules/firewire/sbp_targ/Makefile

@@ -0,0 +1,16 @@
+# $FreeBSD$
+
+# Makefile for the SBP-II Target mode
+
+.PATH: ${.CURDIR}/../../../dev/firewire
+
+KMOD	= sbp_targ
+SRCS	= bus_if.h device_if.h \
+	  opt_cam.h opt_scsi.h \
+	  sbp_targ.c sbp.h \
+	  firewire.h firewirereg.h \
+	  iec13213.h
+
+#CFLAGS += -g
+.include <bsd.kmod.mk>
+