net: axienet: remove unnecessary ftrace-like logging

remove unnecessary ftrace-like logging. Also fixes below
checkpatch WARNING.

WARNING: Unnecessary ftrace-like logging - prefer using ftrace
+       dev_dbg(&ndev->dev, "%s\n", __func__);

Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>