net: macb: ensure interface is not suspended on at91rm9200

net: macb: ensure interface is not suspended on at91rm9200

BugLink: https://bugs.launchpad.net/bugs/1866333
[ Upstream commit e6a41c23df0d5da01540d2abef41591589c0b4be ]

Because of autosuspend, at91ether_start is called with clocks disabled.
Ensure that pm_runtime doesn't suspend the interface as soon as it is
opened as there is no pm_runtime support is the other relevant parts of the
platform support for at91rm9200.

Fixes: d54f89af6cc4 ("net: macb: Add pm runtime support")
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>