[AGPGART] Fix pci_register_driver checking in amd64-agp

pci_register_driver() never returns a positive number.

Signed-off-by: Dave Jones <davej@redhat.com>
diff --git a/drivers/char/agp/amd64-agp.c b/drivers/char/agp/amd64-agp.c
index ac3c33a..e449d94 100644
--- a/drivers/char/agp/amd64-agp.c
+++ b/drivers/char/agp/amd64-agp.c
@@ -761,7 +761,7 @@
 
 	if (agp_off)
 		return -EINVAL;
-	if (pci_register_driver(&agp_amd64_pci_driver) > 0) {
+	if (pci_register_driver(&agp_amd64_pci_driver) < 0) {
 		struct pci_dev *dev;
 		if (!agp_try_unsupported && !agp_try_unsupported_boot) {
 			printk(KERN_INFO PFX "No supported AGP bridge found.\n");