ARM: dts: imx7[d]-mba7: add Ethernet PHY IRQ support

ARM: dts: imx7[d]-mba7: add Ethernet PHY IRQ support

The regulator-fec*-pwdn regulators were used to deassert the PWDN signal
of ethernet PHY, e.g. not powering. This is not necessary as the line
has a pull-up already.
Instead of the combo pad of the PHY for IRQ support.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Markus Niebel <markus.niebel@ew.tq-group.com>
Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>