module: Remove double spaces in module verification taint message

The warning message when loading modules with a wrong signature has
two spaces in it:

"module verification failed: signature and/or  required key missing"

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/kernel/module.c b/kernel/module.c
index 441ed3f..2461370 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3265,7 +3265,7 @@
 	mod->sig_ok = info->sig_ok;
 	if (!mod->sig_ok) {
 		pr_notice_once("%s: module verification failed: signature "
-			       "and/or  required key missing - tainting "
+			       "and/or required key missing - tainting "
 			       "kernel\n", mod->name);
 		add_taint_module(mod, TAINT_UNSIGNED_MODULE, LOCKDEP_STILL_OK);
 	}