riscv: Enable create symlink using kconfig

We select CREATE_ARCH_SYMLINK for RISC-V so that we can have
include/asm/arch linked to include/asm/arch-xyz.
Signed-off-by: NAnup Patel <anup.patel@wdc.com>
Reviewed-by: NBin Meng <bmeng.cn@gmail.com>

arch/Kconfig

@@ -61,6 +61,7 @@ config PPC
 
 config RISCV
 	bool "RISC-V architecture"
+	select CREATE_ARCH_SYMLINK
 	select SUPPORT_OF_CONTROL
 	select OF_CONTROL
 	select DM