platform/x86: dell-smbios-base: Fix error return code in dell_smbios_init

Fix to return the error code -ENODEV when fails to init wmi and
smm.

Fixes: 41e36f2f ("platform/x86: dell-smbios: Link all dell-smbios-* modules together")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Reviewed-by: Mario Limonciello <mario.limonciello@dell.com>
Link: https://lore.kernel.org/r/20201125065032.154125-1-miaoqinglang@huawei.comSigned-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/dell-smbios-base.c

@@ -594,6 +594,7 @@ static int __init dell_smbios_init(void)
 	if (wmi && smm) {
 		pr_err("No SMBIOS backends available (wmi: %d, smm: %d)\n",
 			wmi, smm);
+		ret = -ENODEV;
 		goto fail_create_group;
 	}