platform/x86: mlx-platform: free first dev on error

There is an off-by-one error so we don't unregister priv->pdev_mux[0].
Also it's slightly simpler as a while loop instead of a for loop.

Fixes: 58cbbee2 ("x86/platform/mellanox: Introduce support for Mellanox systems platform")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NVadim Pasternak <vadimp@mellanox.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/mlx-platform.c

@@ -326,7 +326,7 @@ static int __init mlxplat_init(void)
 	return 0;
 
 fail_platform_mux_register:
-	for (i--; i > 0 ; i--)
+	while (--i >= 0)
 		platform_device_unregister(priv->pdev_mux[i]);
 	platform_device_unregister(priv->pdev_i2c);
 fail_alloc: