imx8m{m,n}-venice-gw7902: add support for GPY111 phy

The TI DP83867 phy has been replaced with the MaxLinear GPY111 phy
due to part availability. Add support for it:
 - increase post-reset time to 300ms per datasheet
 - add tx-delay/rx-delay config

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
4 files changed