drivers/isdn: Use static const char * const where possible

Signed-off-by: Joe Perches <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/isdn/pcbit/edss1.c

···
 #include "callbacks.h"
 
 
-char * isdn_state_table[] = {
+const char * const isdn_state_table[] = {
   "Closed",
   "Call initiated",
   "Overlap sending",

drivers/isdn/pcbit/edss1.h

···
 	unsigned long timeout;          /* in seconds */
 };
 
-extern char * isdn_state_table[];
+extern const char * const isdn_state_table[];
 
 void pcbit_fsm_event(struct pcbit_dev *, struct pcbit_chan *,
 		     unsigned short event, struct callb_data *);