pata_ep93xx: fix deferred probing

pata_ep93xx: fix deferred probing

The driver overrides the error codes returned by platform_get_irq() to
-ENXIO, so if it returns -EPROBE_DEFER, the driver would fail the probe
permanently instead of the deferred probing.  Propagate the error code
upstream, as it should have been done from the start...

Fixes: 2fff27512600 ("PATA host controller driver for ep93xx")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omprussia.ru>
Link: https://lore.kernel.org/r/509fda88-2e0d-2cc7-f411-695d7e94b136@omprussia.ru
Signed-off-by: Jens Axboe <axboe@kernel.dk>