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 <lkp@intel.com>
Fixes: 06324664 ("format-security: move static strings to const")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/r/675e7bd9-955b-3ff3-1101-a973b58b5b75@infradead.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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 =