spi: qcom: geni: Simplify DMA setting

As stated in [1], dma_set_mask() with a 64-bit mask will never fail if
dev->dma_mask is non-NULL.
So, if it fails, the 32 bits case will also fail for the same reason.

Simplify code and remove some dead code accordingly.

[1]: https://lkml.org/lkml/2021/6/7/398Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/1b14e4ce91a33c16b2c655389c728071a9c9aa2e.1641643601.git.christophe.jaillet@wanadoo.frSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-geni-qcom.c

@@ -898,11 +898,8 @@ static int spi_geni_probe(struct platform_device *pdev)
 		return irq;
 
 	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
-	if (ret) {
-		ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
 	if (ret)
 		return dev_err_probe(dev, ret, "could not set DMA mask\n");
-	}
 
 	base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(base))