arm:also start devmand on ARM.

Change-Id: Iceffd21d23efa45110a42ce2ab471c15cd6edf66

http://gerrit.minix3.org/#/c/2688/

etc/rc

@@ -173,20 +173,15 @@ autoboot|start)
 	cp /usr/lib/em* /usr/lib/cpp* /lib
     esac
 
-    if [ $ARCH = i386 ]
-    then
     echo -n "Starting hotplugging infrastructure... "
     rm -f /var/run/devmand.pid
     devmand -d /etc/devmand -d /usr/pkg/etc/devmand &
     echo "done."
-    fi
 
     # Things should be alright now.
     ;;
 down|stop)
     sync
-    if [ $ARCH = i386 ]
-    then
     if [ -f /var/run/devmand.pid ]
     then
 	kill -INT `cat /var/run/devmand.pid`
@@ -204,7 +199,6 @@ down|stop)
     then 
 	/usr/pkg/etc/rc.d/usbd stop
     fi
-    fi
 
     # Tell RS server we're going down.
     service shutdown