spi: dw-dma: decrease reference count in dw_spi_dma_init_mfld()

pci_get_device() will increase the reference count for the returned
pci_dev. Since 'dma_dev' is only used to filter the channel in
dw_spi_dma_chan_filer() after using it we need to call pci_dev_put() to
decrease the reference count. Also add pci_dev_put() for the error case.

Fixes: 7063c0d942a1 ("spi/dw_spi: add DMA support")
Signed-off-by: Xiongfeng Wang <[e-mail]>
Acked-by: Serge Semin <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

drivers/spi/spi-dw-dma.c

···
 
 	dw_spi_dma_sg_burst_init(dws);
 
+	pci_dev_put(dma_dev);
+
 	return 0;
 
 free_rxchan:
 	dma_release_channel(dws->rxchan);
 	dws->rxchan = NULL;
 err_exit:
+	pci_dev_put(dma_dev);
 	return -EBUSY;
 }