modpost: change license incompatibility to error() from fatal()

Change fatal() to error() to continue running to report more possible
issues.

There is no difference in the fact that modpost will fail anyway.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/mod/modpost.c

@@ -2145,11 +2145,11 @@ static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
 {
 	switch (exp) {
 	case export_gpl:
-		fatal("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
+		error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
 		      m, s);
 		break;
 	case export_unused_gpl:
-		fatal("GPL-incompatible module %s.ko uses GPL-only symbol marked UNUSED '%s'\n",
+		error("GPL-incompatible module %s.ko uses GPL-only symbol marked UNUSED '%s'\n",
 		      m, s);
 		break;
 	case export_gpl_future: