serial: core: Make uart_parse_options take const char* argument

The pointed string is never modified from within uart_parse_options, so
it should be marked as const in the function prototype.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial_core.c

@@ -1955,9 +1955,10 @@ EXPORT_SYMBOL_GPL(uart_parse_earlycon);
  *	eg: 115200n8r
  */
 void
-uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow)
+uart_parse_options(const char *options, int *baud, int *parity,
+		   int *bits, int *flow)
 {
-	char *s = options;
+	const char *s = options;
 
 	*baud = simple_strtoul(s, NULL, 10);
 	while (*s >= '0' && *s <= '9')

include/linux/serial_core.h

@@ -387,7 +387,7 @@ struct uart_port *uart_get_console(struct uart_port *ports, int nr,
 				   struct console *c);
 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
 			char **options);
-void uart_parse_options(char *options, int *baud, int *parity, int *bits,
+void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
 			int *flow);
 int uart_set_options(struct uart_port *port, struct console *co, int baud,
 		     int parity, int bits, int flow);