platform/x86: mlx-platform: Fix error handling in mlxplat_init()

Add the missing platform_device_unregister() before return
from mlxplat_init() in the error handling case.

Fixes: 6b266e9 ("platform/x86: mlx-platform: Move regmap initialization before all drivers activation")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/mlx-platform.c

@@ -2111,7 +2111,7 @@ static int __init mlxplat_init(void)
 					mlxplat_regmap_config);
 	if (IS_ERR(priv->regmap)) {
 		err = PTR_ERR(priv->regmap);
-		return err;
+		goto fail_alloc;
 	}
 
 	err = mlxplat_mlxcpld_verify_bus_topology(&nr);