get_key_material_https: label 'kfdok' defined but not used

The label 'kfdok' is only used with O_TMPFILE, we need to use
the same #ifdef around this label.

Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Toomas Soome <tsoome@me.com>
Closes #17894

Author: tsoome

lib/libzfs/libzfs_crypto.c

@@ -613,7 +613,9 @@ get_key_material_https(libzfs_handle_t *hdl, const char *uri,
 	(void) unlink(path);
 	free(path);
 
+#ifdef O_TMPFILE
 kfdok:
+#endif
 	if ((key = fdopen(kfd, "r+")) == NULL) {
 		ret = errno;
 		(void) close(kfd);