reset: socfpga: add empty driver allowing consumers to probe

The early reset driver doesn't ever probe, which causes consuming
devices to be unable to probe. Add an empty driver to set this device
as available, allowing consumers to probe.

Signed-off-by: Paweł Anikiel <pan@semihalf.com>
Link: https://lore.kernel.org/r/20210920124141.1166544-4-pan@semihalf.com
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>