RISC-V: Enable module support in defconfig

Signed-off-by: NZong Li <zong@andestech.com>
Signed-off-by: NPalmer Dabbelt <palmer@sifive.com>

arch/riscv/configs/defconfig

@@ -73,3 +73,5 @@ CONFIG_NFS_V4_2=y
 CONFIG_ROOT_NFS=y
 # CONFIG_RCU_TRACE is not set
 CONFIG_CRYPTO_USER_API_HASH=y
+CONFIG_MODULES=y
+CONFIG_MODULE_UNLOAD=y