net: emaclite: Use __func__ instead of hardcoded name

Switch hardcoded function name with a reference to __func__ making
the code more maintainable. Address below checkpatch warning:

WARNING: Prefer using '"%s...", __func__' to using 'xemaclite_mdio_read',
this function's name, in a string
+               "xemaclite_mdio_read(phy_id=%i, reg=%x) == %x\n",

WARNING: Prefer using '"%s...", __func__' to using 'xemaclite_mdio_write',
this function's name, in a string
+               "xemaclite_mdio_write(phy_id=%i, reg=%x, val=%x)\n",

Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>