arm: add initial support for the Phytium Pomelo Board

This adds platform code and the device tree for the Phytium Pomelo Board.
The initial support comprises the UART and the PCIE.

Signed-off-by: weichangzheng <nicholas_zheng@outlook.com>
diff --git a/configs/pomelo_defconfig b/configs/pomelo_defconfig
new file mode 100644
index 0000000..e10eced
--- /dev/null
+++ b/configs/pomelo_defconfig
@@ -0,0 +1,21 @@
+CONFIG_ARM=y
+CONFIG_TARGET_POMELO=y
+CONFIG_SYS_TEXT_BASE=0x180000
+CONFIG_SYS_MALLOC_LEN=0x101000
+CONFIG_NR_DRAM_BANKS=1
+CONFIG_DEFAULT_DEVICE_TREE="phytium-pomelo"
+CONFIG_SYS_PCI_64BIT=y
+CONFIG_DISTRO_DEFAULTS=y
+CONFIG_SYS_LOAD_ADDR=0x90000000
+CONFIG_USE_BOOTARGS=y
+CONFIG_BOOTARGS="console=ttyAMA0,115200 earlycon=pl011,0x28001000 root=/dev/sda2 rw"
+# CONFIG_DISPLAY_CPUINFO is not set
+CONFIG_BOARD_EARLY_INIT_F=y
+CONFIG_LAST_STAGE_INIT=y
+CONFIG_SYS_PROMPT="pomelo#"
+CONFIG_OF_CONTROL=y
+CONFIG_SYS_RELOC_GD_ENV_ADDR=y
+CONFIG_DM_PCI_COMPAT=y
+CONFIG_PCIE_ECAM_GENERIC=y
+CONFIG_PCI_PHYTIUM=y
+CONFIG_PL01X_SERIAL=y