doc: Insert MODULE_ in module-signing macros

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

Documentation/module-signing.txt

@@ -77,11 +77,11 @@ This has a number of options available:
      This presents a choice of which hash algorithm the installation phase will
      sign the modules with:
 
-	CONFIG_SIG_SHA1		"Sign modules with SHA-1"
-	CONFIG_SIG_SHA224	"Sign modules with SHA-224"
-	CONFIG_SIG_SHA256	"Sign modules with SHA-256"
-	CONFIG_SIG_SHA384	"Sign modules with SHA-384"
-	CONFIG_SIG_SHA512	"Sign modules with SHA-512"
+	CONFIG_MODULE_SIG_SHA1		"Sign modules with SHA-1"
+	CONFIG_MODULE_SIG_SHA224	"Sign modules with SHA-224"
+	CONFIG_MODULE_SIG_SHA256	"Sign modules with SHA-256"
+	CONFIG_MODULE_SIG_SHA384	"Sign modules with SHA-384"
+	CONFIG_MODULE_SIG_SHA512	"Sign modules with SHA-512"
 
      The algorithm selected here will also be built into the kernel (rather
      than being a module) so that modules signed with that algorithm can have