serial: liteuart: move polling putchar() function

serial: liteuart: move polling putchar() function

The polling liteuart_putchar() function is only called from methods
conditionally enabled by CONFIG_SERIAL_LITEUART_CONSOLE. Move its
definition closer to the console code where it is dependent on the
same config option.

Signed-off-by: Gabriel Somlo <gsomlo@gmail.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20221123130500.1030189-15-gsomlo@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>