add usbd to nix cpud

Reference: /n/atom/patch/applied2013/cpudusb
Date: Fri Dec 27 20:39:42 CET 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/nix/k10/cpud	Fri Dec 27 20:39:31 2013
+++ /sys/src/nix/k10/cpud	Fri Dec 27 20:39:31 2013
@@ -67,9 +67,9 @@
 	sdaoe
 	sdahci		sdscsifis sdatafis led
 #	sdide		sdscsifis sdatafis
-#	sdodin		sdscsifis sdatafis
-#	sdvanir		sdscsifis sdatafis
-#	sdmpt2		sdscsi
+	sdodin		sdscsifis sdatafis
+	sdvanir		sdscsifis sdatafis
+	sdmpt2		sdscsi
 	sdloop
 
 misc +dev
@@ -84,6 +84,7 @@
 	bootcpud.out boot
 	/amd64/bin/auth/factotum factotum
 	/amd64/bin/ip/ipconfig ipconfig
+	/amd64/bin/usb/usbd usbd
 	/amd64/bin/disk/kfs kfs
 
 conf