riscv: Add Microchip MPFS Icicle board support

This patch adds Microchip MPFS Icicle board support.
For now, NS16550 serial driver is only enabled.
The Microchip MPFS Icicle defconfig by default builds
U-Boot for M-Mode with SMP support.

Signed-off-by: Padmarao Begari <padmarao.begari@microchip.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
diff --git a/configs/microchip_mpfs_icicle_defconfig b/configs/microchip_mpfs_icicle_defconfig
new file mode 100644
index 0000000..a375546
--- /dev/null
+++ b/configs/microchip_mpfs_icicle_defconfig
@@ -0,0 +1,8 @@
+CONFIG_RISCV=y
+CONFIG_ARCH_RV64I=y
+CONFIG_NR_CPUS=5
+CONFIG_TARGET_MICROCHIP_ICICLE=y
+CONFIG_BOOTDELAY=3
+CONFIG_SYS_PROMPT="RISC-V # "
+CONFIG_FIT=y
+CONFIG_OF_PRIOR_STAGE=y