serial: core: Fix ifdef for serial base console functions

If CONFIG_SERIAL_CORE_CONSOLE is not set, we get build errors.
Let's fix the issue by moving the endif after the serial base console
functions.

Fixes: 4547cd76 ("serial: 8250: Fix add preferred console for serial8250_isa_init_ports()")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202404131416.VJljwvkS-lkp@intel.com/Signed-off-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20240413103343.24231-1-tony@atomide.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial_base_bus.c

@@ -219,8 +219,6 @@ static int serial_base_add_one_prefcon(const char *match, const char *dev_name,
 	return ret;
 }
 
-#endif
-
 #ifdef __sparc__
 
 /* Handle Sparc ttya and ttyb options as done in console_setup() */
@@ -319,6 +317,8 @@ int serial_base_add_preferred_console(struct uart_driver *drv,
 	return serial_base_add_one_prefcon(port_match, drv->dev_name, port->line);
 }
 
+#endif
+
 #ifdef CONFIG_SERIAL_8250_CONSOLE
 
 /*