dmaengine: ste_dma40: Fetch disabled channels from DT

Optional properties:

- dma-channels: Number of channels supported by hardware - if not present

		the driver will attempt to obtain the information from H/W

- disabled-channels: Channels which can not be used

Example:

		#dma-cells = <2>;

		memcpy-channels  = <56 57 58 59 60>;

		disabled-channels  = <12>;

		dma-channels = <8>;

	};

			       struct device_node *np)

{

	struct stedma40_platform_data *pdata;

	int num_phy = 0, num_memcpy = 0;

	int num_phy = 0, num_memcpy = 0, num_disabled = 0;

	const const __be32 *list;

	pdata = devm_kzalloc(&pdev->dev,

				   dma40_memcpy_channels,

				   num_memcpy);

	list = of_get_property(np, "disabled-channels", &num_disabled);

	num_disabled /= sizeof(*list);

	if (num_disabled > STEDMA40_MAX_PHYS || num_disabled < 0) {

		d40_err(&pdev->dev,

			"Invalid number of disabled channels specified (%d)\n",

			num_disabled);

		return -EINVAL;

	}

	of_property_read_u32_array(np, "disabled-channels",

				   pdata->disabled_channels,

				   num_disabled);

	pdata->disabled_channels[num_disabled] = -1;

	pdev->dev.platform_data = pdata;

	return 0;