ev3dev hack: trigger UART Rx earlier

this helps improve EV3 UART sensors overflowing the hardware FIFO
at the expense of more CPU usage

Author: dlech

drivers/tty/serial/8250/8250_port.c

@@ -266,7 +266,7 @@ static const struct serial8250_config uart_config[] = {
 		.fifo_size	= 16,
 		.tx_loadsz	= 16,
 		.fcr		= UART_FCR_DMA_SELECT | UART_FCR_ENABLE_FIFO |
-				  UART_FCR_R_TRIG_10,
+				  UART_FCR_R_TRIG_00,
 		.rxtrig_bytes	= {1, 4, 8, 14},
 		.flags		= UART_CAP_FIFO | UART_CAP_AFE,
 	},