MLK-10939-01 net: fec: add stop mode support for dts register set

MLK-10939-01 net: fec: add stop mode support for dts register set

The current driver support stop mode by calling machine api.
The patch add dts support to set gpr register for stop request.

After magic pattern comming during system suspend status, system will
be waked up, and irq handler will be running, there have enet register
access. Since all clocks are disabled in suspend, and clocks are enabled
after resume function. But irq handler run before resume function.

For imx7d chip, access register need some clocks enabled, otherwise system
hang. So the patch also disable wake up irq in the suspend, after resume
back enable the irq, which can avoid system hang issue.

Signed-off-by: Fugang Duan <B38611@freescale.com>
(cherry pick and merge from commit: 8da4f80af0913781a4f9d50917c1dd66180e519d)