net: macb: disable scatter-gather for macb on sama5d3

Create a new configuration for the sama5d3-macb new compatibility string.
This configuration disables scatter-gather because we experienced lock down
of the macb interface of this particular SoC under very high load.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>

Author: noglitch

drivers/net/ethernet/cadence/macb.c

@@ -2861,6 +2861,13 @@ static const struct macb_config at91sam9260_config = {
 	.init = macb_init,
 };
 
+static const struct macb_config sama5d3macb_config = {
+	.caps = MACB_CAPS_SG_DISABLED
+	      | MACB_CAPS_USRIO_HAS_CLKEN | MACB_CAPS_USRIO_DEFAULT_IS_MII_GMII,
+	.clk_init = macb_clk_init,
+	.init = macb_init,
+};
+
 static const struct macb_config pc302gem_config = {
 	.caps = MACB_CAPS_SG_DISABLED | MACB_CAPS_GIGABIT_MODE_AVAILABLE,
 	.dma_burst_length = 16,
@@ -2925,6 +2932,7 @@ static const struct of_device_id macb_dt_ids[] = {
 	{ .compatible = "cdns,gem", .data = &pc302gem_config },
 	{ .compatible = "atmel,sama5d2-gem", .data = &sama5d2_config },
 	{ .compatible = "atmel,sama5d3-gem", .data = &sama5d3_config },
+	{ .compatible = "atmel,sama5d3-macb", .data = &sama5d3macb_config },
 	{ .compatible = "atmel,sama5d4-gem", .data = &sama5d4_config },
 	{ .compatible = "cdns,at91rm9200-emac", .data = &emac_config },
 	{ .compatible = "cdns,emac", .data = &emac_config },