phy: renesas: rcar-gen2: Fix memory leak at error paths

This patch fixes memory leak at error paths of the probe function.
In for_each_child_of_node, if the loop returns, the driver should
call of_put_node() before returns.

Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Fixes: 1233f59f ("phy: Renesas R-Car Gen2 PHY driver")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>