system: trim delay starting udevd

- Apply dracut[1] and void[] linux lessons
 - Drop udev-finish, not needed anymore (2015)

[1]: https://github.com/dracutdevs/dracut/blob/1ff306a3964840fc548188a8aa4862143b347e8a/modules.d/99base/init.sh#L152-L170
[2]: https://github.com/void-linux/void-runit/blob/master/core-services/02-udev.sh

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

system/hotplug.conf

@@ -7,10 +7,11 @@ service nowarn [S12345789] cgroup.system name:udevd pid:udevd log /lib/systemd/s
 service nowarn [S12345789] cgroup.system name:udevd pid:udevd log udevd -- Device event managing daemon
 
 # Wait for udevd to start, then wait a couple of seconds for it to become ready
-run if:udevd cgroup.init    [S] <pid/udevd> sleep 2 --
+run if:udevd cgroup.init    [S] <pid/udevd> udevadm settle -t 0 --
+run if:udevd cgroup.init    [S] <pid/udevd> log udevadm control --reload
 run if:udevd cgroup.init :1 [S] <pid/udevd> log udevadm trigger -c add -t devices    -- Requesting device events
 run if:udevd cgroup.init :2 [S] <pid/udevd> log udevadm trigger -c add -t subsystems -- Requesting subsystem events
-task if:udevd               [S] <pid/udevd> /lib/udev/udev-finish -- Finalizing udev
+run if:udevd cgroup.init    [S] <pid/udevd> log udevadm settle -t 5 -- Waiting for udev to finish
 
 # If udevd is not available, try mdev
 run conflict:udevd [S] mdev -s -- Populating device tree