Removed unnecessary NULL checks introduced in 0a2a0b5a74f4.

Found by Coverity (CID 1478004).
diff --git a/src/njs_parser.c b/src/njs_parser.c
index aae187d..aaa99b6 100644
--- a/src/njs_parser.c
+++ b/src/njs_parser.c
@@ -7827,7 +7827,7 @@
             scope = njs_function_scope(scope->parent);
         }
 
-        if (scope == NULL || scope->type == NJS_SCOPE_GLOBAL) {
+        if (scope->type == NJS_SCOPE_GLOBAL) {
             njs_parser_syntax_error(parser, "\"%V\" object in global scope",
                                     &token->text);
             return NULL;