kbuild: replace abort() with exit(1)

We have had no use of the coredump file for a long time.
So just exit(1) and avoid coredumping.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/scripts/genksyms/lex.l b/scripts/genksyms/lex.l
index fe0dfee..5e544a0 100644
--- a/scripts/genksyms/lex.l
+++ b/scripts/genksyms/lex.l
@@ -392,7 +392,7 @@
       break;
 
     default:
-      abort();
+      exit(1);
     }
 fini: