LoongArch has enabled CONFIG_SMBIOS, but didn't enable CLI '-smbios'.

Fixes: 3efa6fa1 ("hw/loongarch: Add smbios support")
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20230227035905.1290953-2-gaosong@loongson.cn>