serial: punt unused serial_addr()

Only one file apparently defines this function, and it merely stubs
it out. So if no one is defining/calling it, punt it.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

board/barco/barco.c

@@ -340,10 +340,6 @@ void serial_puts (const char *c)
 {
 	return;
 }
-void serial_addr (unsigned int i)
-{
-	return;
-}
 int serial_getc (void)
 {
 	return 0;

include/common.h

@@ -470,7 +470,6 @@ void ft_pci_setup(void *blob, bd_t *bd);
 /* $(CPU)/serial.c */
 int	serial_init   (void);
 void	serial_exit   (void);
-void	serial_addr   (unsigned int);
 void	serial_setbrg (void);
 void	serial_putc   (const char);
 void	serial_putc_raw(const char);