x86/PCI: Expose VMD's pci_dev in struct pci_sysdata

Expose VMD's pci_dev pointer in struct pci_sysdata.  This will be used
indirectly by intel-iommu.c to find the correct domain.

Link: https://lore.kernel.org/r/1579613871-301529-3-git-send-email-jonathan.derrick@intel.com
[bhelgaas: commit log]
Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Christoph Hellwig <hch@lst.de>

arch/x86/include/asm/pci.h

@@ -25,7 +25,7 @@ struct pci_sysdata {
 	void		*fwnode;	/* IRQ domain for MSI assignment */
 #endif
 #if IS_ENABLED(CONFIG_VMD)
-	bool vmd_domain;		/* True if in Intel VMD domain */
+	struct pci_dev	*vmd_dev;	/* VMD Device if in Intel VMD domain */
 #endif
 };
 
@@ -64,7 +64,7 @@ static inline void *_pci_root_bus_fwnode(struct pci_bus *bus)
 #if IS_ENABLED(CONFIG_VMD)
 static inline bool is_vmd(struct pci_bus *bus)
 {
-	return to_pci_sysdata(bus)->vmd_domain;
+	return to_pci_sysdata(bus)->vmd_dev != NULL;
 }
 #else
 #define is_vmd(bus)		false

drivers/pci/controller/vmd.c

@@ -679,7 +679,7 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
 		.parent = res,
 	};
 
-	sd->vmd_domain = true;
+	sd->vmd_dev = vmd->dev;
 	sd->domain = vmd_find_free_domain();
 	if (sd->domain < 0)
 		return sd->domain;