arm64: dts: imx8mn-var-som: add 20ms delay to ethernet regulator enable

[Hugo Villeneuve <hugo@xxxxxxxxxxx>]

Hi,
the following patch:

26ca44bdbd13 arm64: dts: imx8mn-var-som: add 20ms delay to ethernet
regulator enable

Was introduced in kernel 6.5.

It needs to be applied to the stable kernels:
  6.1
  6.2
  6.3
  6.4

Without it, the PHY is not detected and the ethernet port is not
working.

Tested on a custom board with a Variscite IMX8MN NANO SOM for the
following stable kernels:
  6.1
  6.2
  6.3
  6.4

Hugo Villeneuve