at803x: fix reset handling

The driver of course "knows" that the chip's reset signal is active low,
so  it drives the GPIO to 0  to reset the PHY and to 1 otherwise; however
all this will only work iff the GPIO  is  specified as active-high in the
device tree!  I think both the driver and the device trees (if there are
any -- I was unable to find them) need to be fixed in this case...

Fixes: 13a56b44

 ("net: phy: at803x: Add support for hardware reset")
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>