riscv: ax25: Add platform-specific Kconfig options

Add ax25 RISC-V platform-specific Kconfig options,
to include CPU and timer drivers. Also disable
ATCPIT100 SoC timer and replace by PLMT.

Signed-off-by: Rick Chen <rick@andestech.com>
Cc: Greentime Hu <greentime@andestech.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
diff --git a/arch/riscv/cpu/ax25/Kconfig b/arch/riscv/cpu/ax25/Kconfig
index e9dbca2..68bd4e9 100644
--- a/arch/riscv/cpu/ax25/Kconfig
+++ b/arch/riscv/cpu/ax25/Kconfig
@@ -1,5 +1,11 @@
 config RISCV_NDS
 	bool
+	select ARCH_EARLY_INIT_R
+	imply CPU
+	imply CPU_RISCV
+	imply RISCV_TIMER
+	imply ANDES_PLIC if RISCV_MMODE
+	imply ANDES_PLMT if RISCV_MMODE
 	help
 	  Run U-Boot on AndeStar V5 platforms and use some specific features
 	  which are provided by Andes Technology AndeStar V5 families.