ppc: qemu: Switch over to use DM serial

The QEMU ppce500 target integrates 2 NS16550 serial ports. Switch
over to use the DM version of the driver by:

- drop unnecessary ad-hoc config macros
- add get_serial_clock() in the board codes
Signed-off-by: NBin Meng <bmeng.cn@gmail.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>
Reviewed-by: NPriyanka Jain <priyanka.jain@nxp.com>

board/freescale/qemu-ppce500/qemu-ppce500.c

@@ -374,3 +374,9 @@ void *board_fdt_blob_setup(void)
 {
 	return get_fdt_virt();
 }
+
+/* See CONFIG_SYS_NS16550_CLK in arch/powerpc/include/asm/config.h */
+int get_serial_clock(void)
+{
+	return get_bus_freq(0);
+}

configs/qemu-ppce500_defconfig

@@ -30,6 +30,7 @@ CONFIG_SYS_RELOC_GD_ENV_ADDR=y
 CONFIG_DM=y
 # CONFIG_MMC is not set
 CONFIG_E1000=y
+CONFIG_DM_SERIAL=y
 CONFIG_SYS_NS16550=y
 CONFIG_ADDR_MAP=y
 CONFIG_PANIC_HANG=y

include/configs/qemu-ppce500.h

@@ -73,16 +73,6 @@ extern unsigned long long get_phys_ccsrbar_addr_early(void);
 #define CONFIG_SYS_MONITOR_LEN		(512 * 1024)
 #define CONFIG_SYS_MALLOC_LEN		(4 * 1024 * 1024)
 
-#define CONFIG_SYS_NS16550_SERIAL
-#define CONFIG_SYS_NS16550_REG_SIZE	1
-#define CONFIG_SYS_NS16550_CLK		(get_bus_freq(0))
-
-#define CONFIG_SYS_BAUDRATE_TABLE	\
-	{300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200}
-
-#define CONFIG_SYS_NS16550_COM1	(CONFIG_SYS_CCSRBAR+0x4500)
-#define CONFIG_SYS_NS16550_COM2	(CONFIG_SYS_CCSRBAR+0x4600)
-
 /*
  * General PCI
  * Memory space is mapped 1-1, but I/O space must start from 0.