net: mvpp2.c: Clear all buffer / descriptor areas before usage

This fixes problems noticed with the PPv2.2 A7k/8k port, when not all
elements of the descriptors had been cleared before use.

Signed-off-by: Stefan Roese <sr@denx.de>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
diff --git a/drivers/net/mvpp2.c b/drivers/net/mvpp2.c
index 06909e6..b9e0fdc 100644
--- a/drivers/net/mvpp2.c
+++ b/drivers/net/mvpp2.c
@@ -4429,6 +4429,9 @@
 		size += RX_BUFFER_SIZE;
 	}
 
+	/* Clear the complete area so that all descriptors are cleared */
+	memset(bd_space, 0, size);
+
 	/* Save base addresses for later use */
 	priv->base = (void *)dev_get_addr_index(dev, 0);
 	if (IS_ERR(priv->base))