arm: ls1021atwr: Convert to driver model and enable serial support

Convert ls1021atwr_nor to driver model support. As a start, enable
ns16550 serial port driver.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>

arch/arm/dts/ls1021a-twr.dts

@@ -19,6 +19,10 @@
 		spi0 = &qspi;
 		spi1 = &dspi1;
 	};
+
+	chosen {
+		stdout-path = &uart0;
+	};
 };
 
 &qspi {

arch/arm/dts/ls1021a.dtsi

@@ -218,7 +218,6 @@
 			compatible = "fsl,16550-FIFO64", "ns16550a";
 			reg = <0x21c0500 0x100>;
 			interrupts = <GIC_SPI 86 IRQ_TYPE_LEVEL_HIGH>;
-			clock-frequency = <0>;
 			fifo-size = <15>;
 			status = "disabled";
 		};
@@ -227,7 +226,6 @@
 			compatible = "fsl,16550-FIFO64", "ns16550a";
 			reg = <0x21c0600 0x100>;
 			interrupts = <GIC_SPI 86 IRQ_TYPE_LEVEL_HIGH>;
-			clock-frequency = <0>;
 			fifo-size = <15>;
 			status = "disabled";
 		};
@@ -236,7 +234,6 @@
 			compatible = "fsl,16550-FIFO64", "ns16550a";
 			reg = <0x21d0500 0x100>;
 			interrupts = <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
-			clock-frequency = <0>;
 			fifo-size = <15>;
 			status = "disabled";
 		};
@@ -245,7 +242,6 @@
 			compatible = "fsl,16550-FIFO64", "ns16550a";
 			reg = <0x21d0600 0x100>;
 			interrupts = <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
-			clock-frequency = <0>;
 			fifo-size = <15>;
 			status = "disabled";
 		};

configs/ls1021atwr_nor_defconfig

@@ -1,6 +1,10 @@
 CONFIG_ARM=y
 CONFIG_TARGET_LS1021ATWR=y
+CONFIG_DM_SERIAL=y
+CONFIG_DEFAULT_DEVICE_TREE="ls1021a-twr"
 # CONFIG_CMD_SETEXPR is not set
+CONFIG_OF_CONTROL=y
+CONFIG_DM=y
 CONFIG_NETDEVICES=y
 CONFIG_E1000=y
 CONFIG_SYS_NS16550=y

include/configs/ls1021atwr.h

@@ -271,7 +271,9 @@
 #else
 #define CONFIG_CONS_INDEX		1
 #define CONFIG_SYS_NS16550_SERIAL
+#ifndef CONFIG_DM_SERIAL
 #define CONFIG_SYS_NS16550_REG_SIZE	1
+#endif
 #define CONFIG_SYS_NS16550_CLK		get_serial_clock()
 #endif