cdx: don't select CONFIG_GENERIC_MSI_IRQ

x86 does not use CONFIG_GENERIC_MSI_IRQ, and trying to enable it anyway
results in a build failure:

In file included from include/linux/ssb/ssb.h:10,
from drivers/ssb/pcihost_wrapper.c:18:
include/linux/gpio/driver.h:41:33: error: field 'msiinfo' has incomplete type
41 | msi_alloc_info_t msiinfo;
| ^~~~~~~
In file included from include/linux/kvm_host.h:19,
from arch/x86/events/intel/core.c:17:
include/linux/msi.h:528:33: error: field 'alloc_info' has incomplete type
528 | msi_alloc_info_t alloc_info;

Change the driver to actually build without this symbol and remove the
incorrect 'select' statements.

Fixes: e8b18c11731d ("cdx: Fix missing GENERIC_MSI_IRQ on compile test")
Reviewed-by: Robin Murphy <[e-mail]>
Reviewed-by: Nikhil Agarwal <[e-mail]>
Signed-off-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Nipun Gupta <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alex Williamson <[e-mail]>

drivers/cdx/Kconfig

···
 config CDX_BUS
 	bool "CDX Bus driver"
 	depends on OF && ARM64 || COMPILE_TEST
-	select GENERIC_MSI_IRQ
 	help
 	  Driver to enable Composable DMA Transfer(CDX) Bus. CDX bus
 	  exposes Fabric devices which uses composable DMA IP to the

drivers/cdx/cdx.c

···
 	 * Setup MSI device data so that generic MSI alloc/free can
 	 * be used by the device driver.
 	 */
-	if (cdx->msi_domain) {
+	if (IS_ENABLED(CONFIG_GENERIC_MSI_IRQ) && cdx->msi_domain) {
 		error = msi_setup_device_data(&cdx_dev->dev);
 		if (error)
 			return error;
···
 		     ((cdx->id << CDX_CONTROLLER_ID_SHIFT) | (cdx_dev->bus_num & CDX_BUS_NUM_MASK)),
 		     cdx_dev->dev_num);
 
-	if (cdx->msi_domain) {
+	if (IS_ENABLED(CONFIG_GENERIC_MSI_IRQ) && cdx->msi_domain) {
 		cdx_dev->num_msi = dev_params->num_msi;
 		dev_set_msi_domain(&cdx_dev->dev, cdx->msi_domain);
 	}

drivers/cdx/controller/Kconfig

···
 config CDX_CONTROLLER
 	tristate "CDX bus controller"
 	depends on HAS_DMA
-	select GENERIC_MSI_IRQ
 	select REMOTEPROC
 	select RPMSG
 	help

drivers/cdx/controller/cdx_controller.c

···
 	cdx->ops = &cdx_ops;
 
 	/* Create MSI domain */
-	cdx->msi_domain = cdx_msi_domain_init(&pdev->dev);
+	if (IS_ENABLED(CONFIG_GENERIC_MSI_IRQ))
+		cdx->msi_domain = cdx_msi_domain_init(&pdev->dev);
 	if (!cdx->msi_domain) {
 		ret = dev_err_probe(&pdev->dev, -ENODEV, "cdx_msi_domain_init() failed");
 		goto cdx_msi_fail;