pata_ipx4xx_cf: fix IRQ check

[ Upstream commit e379b40cc0f179403ce0b82b7e539f635a568da5 ]

The driver's probe() method is written as if platform_get_irq() returns 0
on error, while actually it returns a negative error code (with all the
other values considered valid IRQs).  Rewrite the driver's IRQ checking
code to pass the positive IRQ #s to ata_host_activate(), propagate errors
upstream, and treat IRQ0 as error, returning -EINVAL, as the libata code
treats 0  as  an indication that polling should be used anyway...

Fixes: 0df0d0a0 ("[libata] ARM: add ixp4xx PATA driver")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omprussia.ru>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>