ata: pata_ep93xx: fix error return code in probe

Return -ENOMEM from ep93xx_pata_probe() if devm_kzalloc() or
ata_host_alloc() fails.

Signed-off-by: Nikita Shubin <nikita.shubin@maquefel.me>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>