feat(dracut-install): add fw_devlink suppliers as module dependencies

feat(dracut-install): add fw_devlink suppliers as module dependencies

Dracut currently finds kernel module dependencies using two methods:
depmod and softdeps. However, these are often insufficient on embedded
systems where a lot of driver dependencies are only described in the
device tree. This is often the case for low-level devices such as
clocks, regulators, pinctrls, etc.

This patch allows dracut to find those device tree dependencies, by
parsing the sysfs supplier nodes populated by fw_devlink.

Signed-off-by: Adrien Thierry <athierry@redhat.com>