tty: n_hdlc: fix build on SPARC

Fix tty driver build on SPARC by not using __exitdata.
It appears that SPARC does not support section .exit.data.

Fixes these build errors:

`.exit.data' referenced in section `.exit.text' of drivers/tty/n_hdlc.o: defined in discarded section `.exit.data' of drivers/tty/n_hdlc.o
`.exit.data' referenced in section `.exit.text' of drivers/tty/n_hdlc.o: defined in discarded section `.exit.data' of drivers/tty/n_hdlc.o
`.exit.data' referenced in section `.exit.text' of drivers/tty/n_hdlc.o: defined in discarded section `.exit.data' of drivers/tty/n_hdlc.o
`.exit.data' referenced in section `.exit.text' of drivers/tty/n_hdlc.o: defined in discarded section `.exit.data' of drivers/tty/n_hdlc.o

Reported-by: kbuild test robot <[email protected]>
Fixes: 0632466 ("format-security: move static strings to const")
Signed-off-by: Randy Dunlap <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Andrew Morton <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: rddunlap

drivers/tty/n_hdlc.c

@@ -968,6 +968,11 @@ static int __init n_hdlc_init(void)
 
 }	/* end of init_module() */
 
+#ifdef CONFIG_SPARC
+#undef __exitdata
+#define __exitdata
+#endif
+
 static const char hdlc_unregister_ok[] __exitdata =
 	KERN_INFO "N_HDLC: line discipline unregistered\n";
 static const char hdlc_unregister_fail[] __exitdata =