ARM: dts: am335x-bone-common: Add GPIO PHY reset on revision C3 board

ARM: dts: am335x-bone-common: Add GPIO PHY reset on revision C3 board

This patch adds ethernet PHY reset GPIO config for Beaglebone Black
series boards with revision C3. This fixes a random phy startup failure
bug discussed at [1]. The GPIO pin used for reset is not used on older
revisions, so it is ok to apply to all board revisions. The reset timing
was discussed and tested at [2].

[1] https://forum.digikey.com/t/ethernet-device-is-not-detecting-on-ubuntu-20-04-lts-on-bbg/19948
[2] https://forum.beagleboard.org/t/recognizing-a-beaglebone-black-rev-c3-board/31249/

Signed-off-by: Robert Nelson <robertcnelson@gmail.com>
Signed-off-by: Shengyu Qu <wiagn233@outlook.com>
Message-ID: <TY3P286MB26113797A3B2EC7E0348BBB2980FA@TY3P286MB2611.JPNP286.PROD.OUTLOOK.COM>
Signed-off-by: Tony Lindgren <tony@atomide.com>