Instead of returning an invalid device capability when a device
is (not yet) available, e.g. a PCI device is requested before the
PCI bus got parsed accordingly, we check the device capability
within the Platform::Connection utilities, and register temporarily
an Io_signal_handler to wait for changes of the devices ROM, and
try the device aquisition again. Thereby, simple drivers so not have
to take the burden to do so.
To enable this feature for all drivers, we always have to export a
devices ROM, but limit the information about physical resources
(I/O memory addresses, IRQ numbers, I/O port ranges) to clients with
'info=yes' in their policy description.
Fixgenodelabs/genode#4496
