net: ethernet: fec_main: Add "phy-reset-in-suspend" device tree option. When this...

net: ethernet: fec_main: Add "phy-reset-in-suspend" device tree option. When this option is
present, the driver will assert the phy reset line during suspend.
There are two main reasons to set this configuration:
- Avoid that the phy reset line "powers" the phy when the phy power
  is turned off.
- Ensure that the phy is reset when waking up from suspend, what
  helps to ensure proper operation when the phy power is turned off.

Based on: https://github.com/digi-embedded/linux/commit/f0ddbc0153b269bfd21b84dbd4ad16acdfd21f29

Signed-off-by: Josep Orga <jorga@somdevices.com>