doc: put proper reference to CONFIG_MODULE_SIG_ENFORCE

Signed-off-by: NPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Documentation/kernel-parameters.txt

@@ -1625,7 +1625,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 	module.sig_enforce
 			[KNL] When CONFIG_MODULE_SIG is set, this means that
 			modules without (valid) signatures will fail to load.
-			Note that if CONFIG_MODULE_SIG_ENFORCE is set, that
+			Note that if CONFIG_MODULE_SIG_FORCE is set, that
 			is always true, so this option does nothing.
 
 	mousedev.tap_time=