tty: serial: atmel: use macros instead of hardcoded values

Use UART_PM_STATE_ON, UART_PM_STATE_OFF instead of hardcoded values.

Reviewed-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20211007112014.2332019-1-claudiu.beznea@microchip.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>