ata: pata_pxa: Fix DMA channel leak on probe error

ata: pata_pxa: Fix DMA channel leak on probe error

When dmaengine_slave_config() fails, the DMA channel acquired by
dma_request_chan() is not released before returning the error,
leaking the channel reference.

Fix by adding dma_release_channel() in the error path.

The ata_host_activate() error path already correctly releases the
DMA channel.

Cc: stable@vger.kernel.org
Fixes: 88622d80af82 ("ata: pata_pxa: dmaengine conversion")
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>