DMA device is expected to be available while SPI transfer is ongoing.

Prevent usage of potentially stale DMA device by keeping reference
count till the end of the transfer.

Fixes: 4d986ffa ("spi: add missing pci_dev_put() before return")
Reported-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220307173740.80996-1-andriy.shevchenko@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>