spi: pca2xx-pci: Allow MSI

Now that the core is ready for edge-triggered interrupts, we can safely
allow the PCI versions that provide this to enable the feature and,
thus, have less shared interrupts.

Signed-off-by: Jan Kiszka <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Reviewed-by: Jarkko Nikula <[e-mail]>
Signed-off-by: Mark Brown <[e-mail]>

drivers/spi/spi-pxa2xx-pci.c

···
 	ssp = &spi_pdata.ssp;
 	ssp->phys_base = pci_resource_start(dev, 0);
 	ssp->mmio_base = pcim_iomap_table(dev)[0];
-	ssp->irq = dev->irq;
 	ssp->port_id = (c->port_id >= 0) ? c->port_id : dev->devfn;
 	ssp->type = c->type;
+
+	pci_set_master(dev);
+
+	ret = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_ALL_TYPES);
+	if (ret < 0)
+		return ret;
+	ssp->irq = pci_irq_vector(dev, 0);
 
 	snprintf(buf, sizeof(buf), "pxa2xx-spi.%d", ssp->port_id);
 	ssp->clk = clk_register_fixed_rate(&dev->dev, buf , NULL, 0,