serial: efm32: use $vendor,$device scheme for compatible string

Wolfram Sang pointed out that "efm32,$device" is non-standard. So use the
common scheme and prefix device with "efm32-". The old compatible string
is left in place until arch/arm/boot/dts/efm32* is fixed.

Reported-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/efm32-uart.c

@@ -798,6 +798,9 @@ static int efm32_uart_remove(struct platform_device *pdev)
 
 static const struct of_device_id efm32_uart_dt_ids[] = {
 	{
+		.compatible = "energymicro,efm32-uart",
+	}, {
+		/* doesn't follow the "vendor,device" scheme, don't use */
 		.compatible = "efm32,uart",
 	}, {
 		/* sentinel */