w1: omap-hdq: fix error return code in omap_hdq_probe()

platform_get_irq() returns an error code, but the omap_hdq
driver ignores it and always returns -ENXIO. This is not correct,
and prevents -EPROBE_DEFER from being propagated properly.
Notice that platform_get_irq() no longer returns 0 on error.

Print error message and propagate the return value of
platform_get_irq on failure.

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>