net: ti: icssg_prueth: Fix NULL pointer dereference in prueth_probe()

In the Linux kernel, the following vulnerability has been resolved: net: ti: icssg_prueth: Fix NULL pointer dereference in prueth_probe() In the prueth_probe() function, if one of the calls to emac_phy_connect() fails due to of_phy_connect() returning NULL, then the subsequent call to phy_attached_info() will dereference a NULL pointer. Check the return code of emac_phy_connect and fail cleanly if there is an error.