[PATCH] Fix aic7xxx_osm.c compile with older gcc's

My version of gcc doesn't warn about this error (declaration in the
middle of a set of statements).

The fix is simple (this also corrects return code; for init functions it
should be zero or error). 

drivers/scsi/aic7xxx/aic7xxx_osm.c

@@ -3605,9 +3605,8 @@ ahc_linux_init(void)
 	ahc_linux_transport_template = spi_attach_transport(&ahc_linux_transport_functions);
 	if (!ahc_linux_transport_template)
 		return -ENODEV;
-	int rc = ahc_linux_detect(&aic7xxx_driver_template);
-	if (rc)
-		return rc;
+	if (ahc_linux_detect(&aic7xxx_driver_template))
+		return 0;
 	spi_release_transport(ahc_linux_transport_template);
 	ahc_linux_exit();
 	return -ENODEV;