net: phy: Handle not having GPIO enabled in the kernel

If CONFIG_GPIOLIB is disabled, fwnode_get_named_gpiod() becomes a stub
function, which return -ENOSYS. Handle this in the same way as
-ENOENT, i.e. assume there is no GPIO used to reset the PHYs.

Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Fixes: bafbdd52 ("phylib: Add device reset GPIO support")
Signed-off-by: David S. Miller <davem@davemloft.net>