Free correct memory in zfs_get_pci_slots_sys_path()

Coverity found this. We incorrectly attempt to free tmp, which we should
be freeing path.

Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>

lib/libzutil/os/linux/zutil_device_path_os.c

@@ -273,7 +273,7 @@ zfs_get_pci_slots_sys_path(const char *dev_name)
 			free(address2);
 			if (asprintf(&path, "/sys/bus/pci/slots/%s",
 			    ep->d_name) == -1) {
-				free(tmp);
+				free(path);
 				continue;
 			}
 			break;