net: Convert some ethtool_sprintf() to ethtool_puts()

This patch converts some basic cases of ethtool_sprintf() to
ethtool_puts().

The conversions are used in cases where ethtool_sprintf() was being used
with just two arguments:
|       ethtool_sprintf(&data, buffer[i].name);
or when it's used with format string: "%s"
|       ethtool_sprintf(&data, "%s", buffer[i].name);
which both now become:
|       ethtool_puts(&data, buffer[i].name);

Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>