libchip/serial: Add const qualifier

c/src/lib/libcpu/arm/at91rm9200/dbgu/dbgu.c

@@ -35,7 +35,7 @@ static void    dbgu_write_polled(int minor, char c);
 static int     dbgu_set_attributes(int minor, const struct termios *t);
 
 /* Pointers to functions for handling the UART. */
-console_fns dbgu_fns =
+const console_fns dbgu_fns =
 {
     libchip_serial_default_probe,
     dbgu_first_open,

c/src/lib/libcpu/arm/at91rm9200/usart/usart.c

@@ -37,7 +37,7 @@ static int     usart_set_attributes(int minor, const struct termios *t);
 at91rm9200_usart_regs_t *usart_get_base(int minor);
 
 /* Pointers to functions for handling the UART polled. */
-console_fns usart_polling_fns = {
+const console_fns usart_polling_fns = {
   libchip_serial_default_probe,       /* deviceProbe */
   usart_first_open,                   /* deviceFirstOpen */
   usart_last_close,                   /* deviceLastClose */

c/src/lib/libcpu/arm/pxa255/ffuart/ffuart.c

@@ -29,7 +29,7 @@ static void    ffuart_write_polled(int minor, char c);
 static int     ffuart_set_attributes(int minor, const struct termios *t);
 
 /* Pointers to functions for handling the UART. */
-console_fns ffuart_fns =
+const console_fns ffuart_fns =
 {
     libchip_serial_default_probe,
     ffuart_first_open,

c/src/lib/libcpu/mips/mongoosev/duart/mg5uart.c

@@ -893,7 +893,7 @@ MG5UART_STATIC void mg5uart_enable_interrupts(
  * Flow control is only supported when using interrupts
  */
 
-console_fns mg5uart_fns =
+const console_fns mg5uart_fns =
 {
   libchip_serial_default_probe,   /* deviceProbe */
   mg5uart_open,                   /* deviceFirstOpen */
@@ -906,7 +906,7 @@ console_fns mg5uart_fns =
   TRUE                            /* deviceOutputUsesInterrupts */
 };
 
-console_fns mg5uart_fns_polled =
+const console_fns mg5uart_fns_polled =
 {
   libchip_serial_default_probe,        /* deviceProbe */
   mg5uart_open,                        /* deviceFirstOpen */

c/src/lib/libcpu/mips/mongoosev/duart/mg5uart.h

@@ -73,8 +73,8 @@ extern "C" {
  * Driver function table
  */
 
-extern console_fns mg5uart_fns;
-extern console_fns mg5uart_fns_polled;
+extern const console_fns mg5uart_fns;
+extern const console_fns mg5uart_fns_polled;
 
 /*
  * Default register access routines