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/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 0d04d91..8cfc7d0 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -11,6 +11,9 @@
 config TARGET_AX25_AE350
 	bool "Support ax25-ae350"
 
+config TARGET_MICROCHIP_ICICLE
+	bool "Support Microchip PolarFire-SoC Icicle Board"
+
 config TARGET_QEMU_VIRT
 	bool "Support QEMU Virt Board"
 
@@ -48,6 +51,7 @@
 # board-specific options below
 source "board/AndesTech/ax25-ae350/Kconfig"
 source "board/emulation/qemu-riscv/Kconfig"
+source "board/microchip/mpfs_icicle/Kconfig"
 source "board/sifive/fu540/Kconfig"
 
 # platform-specific options below