net: fec: prevent undesired de-assertion of phy-reset on request

When gpio_request_by_name allocates a gpio output it by default will
de-assert the gpio which for phy-reset will take the PHY out of reset.
As this occurs before fec_gpio_reset is called to assert the reset
line it can cause undesired affects if reset timings are not properly
met.

Configure the gpio with GPIOD_IS_OUT_ACTIVE so that reset is kept active
(reset asserted) to avoid this.

Cc: Sean Anderson <sean.anderson@seco.com>
Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Tested-by: Adam Ford <aford173@gmail.com> #imx8mm-beacon
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>