km/uart: port UART interface of KM Kirkwood boards to driver model

Activate the driver model for the serial interface in the KM Kirkwood
Kconfig file. The associated preprocessor definitions could be removed
from the header file. However, the clock of 200 MHz needs to be declared
in the device tree.
Signed-off-by: NPascal Linder <pascal.linder@edu.hefr.ch>
Signed-off-by: NHolger Brunck <holger.brunck@ch.abb.com>
Signed-off-by: NStefan Roese <sr@denx.de>

arch/arm/dts/kirkwood-km_common.dtsi

@@ -22,6 +22,7 @@
 
 		serial@12000 {
 			status = "okay";
+			clock-frequency = <200000000>;
 		};
 	};
 

board/keymile/km_arm/Kconfig

@@ -42,6 +42,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	def_bool y
 	select BOARD_LATE_INIT
 	select DM
+	select DM_SERIAL
 	select DM_SPI
 	select DM_SPI_FLASH
 	imply CMD_CRAMFS

include/configs/km/km_arm.h

@@ -60,15 +60,6 @@
 
 #define CONFIG_SKIP_LOWLEVEL_INIT	/* disable board lowlevel_init */
 
-/*
- * NS16550 Configuration
- */
-#define CONFIG_SYS_NS16550_SERIAL
-#define CONFIG_SYS_NS16550_REG_SIZE	(-4)
-#define CONFIG_SYS_NS16550_CLK		CONFIG_SYS_TCLK
-#define CONFIG_SYS_NS16550_COM1		KW_UART0_BASE
-#define CONFIG_SYS_NS16550_COM2		KW_UART1_BASE
-
 /*
  * For booting Linux, the board info and command line data
  * have to be in the first 8 MB of memory, since this is