net: ravb: Detect PHY correctly

The order of parameters passed to the phy_connect() was wrong.
Moreover, only PHY address 0 was used. Replace this with code
capable of detecting the PHY address.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>