Remove unnecessary NULL check

Addressing:
/home/jcerny/openscap/src/OVAL/probes/SEAP/sexp-manip.c: In function ‘SEXP_datatype_set_nth’:
/home/jcerny/openscap/src/OVAL/probes/SEAP/sexp-manip.c:1921:27: warning: nonnull argument ‘name’ compared to NULL [-Wnonnull-compare]
  if (list == NULL || name == NULL) {

Author: jan-cerny

src/OVAL/probes/SEAP/sexp-manip.c

@@ -1918,7 +1918,7 @@ int SEXP_datatype_set_nth (SEXP_t *list, uint32_t n, const char *name)
         SEXP_val_t v_dsc;
         SEXP_t    *s_nth;
 
-	if (list == NULL || name == NULL) {
+	if (list == NULL) {
 		errno = EFAULT;
 		return -1;
 	}