pci-swiotlb-xen: call pci_request_acs only ifdef CONFIG_PCI

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c
index 9695704..0e98e5d 100644
--- a/arch/x86/xen/pci-swiotlb-xen.c
+++ b/arch/x86/xen/pci-swiotlb-xen.c
@@ -75,8 +75,10 @@
 		xen_swiotlb_init(1, true /* early */);
 		dma_ops = &xen_swiotlb_dma_ops;
 
+#ifdef CONFIG_PCI
 		/* Make sure ACS will be enabled */
 		pci_request_acs();
+#endif
 	}
 }
 
@@ -92,8 +94,10 @@
 		return rc;
 
 	dma_ops = &xen_swiotlb_dma_ops;
+#ifdef CONFIG_PCI
 	/* Make sure ACS will be enabled */
 	pci_request_acs();
+#endif
 
 	return 0;
 }