xen/pciback: miscellaneous adjustments

This is a minor bugfix and a set of small cleanups; as it is not clear
whether this needs splitting into pieces (and if so, at what
granularity), it is a single combined patch.
- add a missing return statement to an error path in
  kill_domain_by_device()
- use pci_is_enabled() rather than raw atomic_read()
- remove a bogus attempt to zero-terminate an already zero-terminated
  string
- #define DRV_NAME once uniformly in the shared local header
- make DRIVER_ATTR() variables static
- eliminate a pointless use of list_for_each_entry_safe()
- add MODULE_ALIAS()
- a little bit of constification
- adjust a few messages
- remove stray semicolons from inline function definitions

Signed-off-by: Jan Beulich <jbeulich@suse.com>
[v1: Dropped the resource_size fix, altered the description]
[v2: Fixed cleanpatch.pl comments]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/xen/xen-pciback/vpci.c

@@ -12,7 +12,6 @@
 #include "pciback.h"
 
 #define PCI_SLOT_MAX 32
-#define DRV_NAME	"xen-pciback"
 
 struct vpci_dev_data {
 	/* Access to dev_list must be protected by lock */
@@ -150,9 +149,9 @@ static void __xen_pcibk_release_pci_dev(struct xen_pcibk_device *pdev,
 	spin_lock_irqsave(&vpci_dev->lock, flags);
 
 	for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
-		struct pci_dev_entry *e, *tmp;
-		list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot],
-					 list) {
+		struct pci_dev_entry *e;
+
+		list_for_each_entry(e, &vpci_dev->dev_list[slot], list) {
 			if (e->dev == dev) {
 				list_del(&e->list);
 				found_dev = e->dev;
@@ -247,7 +246,7 @@ static int __xen_pcibk_get_pcifront_dev(struct pci_dev *pcidev,
 	return found;
 }
 
-struct xen_pcibk_backend xen_pcibk_vpci_backend = {
+const struct xen_pcibk_backend xen_pcibk_vpci_backend = {
 	.name		= "vpci",
 	.init		= __xen_pcibk_init_devices,
 	.free		= __xen_pcibk_release_devices,