net: zynq_gem: Modify phy supported features after max-speed was set

The phydev supported features were reset in phy_set_supported() so,
move the setting of driver supported features after this so that it
wont lost in phy_set_supported().

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>