package/eudev: tweak initscript

Make the udev initscript trigger in a coherent way, i.e. first set
subsystems, then device and then let the whole thing settle.
Otherwise for usb_modeswitch udev rules they never kick in since the
storage aspect (device) gets claimed first and the switch ignored.
Also set the settle timeout to a smaller value than the default
120 seconds to avoid stalling too much.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>