Merge branch 'ARM-Enable-GENET-support-for-RPi-4'

Stefan Wahren says:

====================
ARM: Enable GENET support for RPi 4

Raspberry Pi 4 uses the broadcom genet chip in version five.
This chip has a dma controller integrated. Up to now the maximal
burst size was hard-coded to 0x10. But it turns out that Raspberry Pi 4
does only work with the smaller maximal burst size of 0x8.

Additionally the patch series has some IRQ retrieval improvements and
adds support for a missing PHY mode.

This series based on Matthias Brugger's V1 series [1].

[1] - https://patchwork.kernel.org/cover/11186193/

Changes in V5:
- address Doug's comment

Changes in V4:
- rebased on current net-next
- remove RGMII_ID support
- remove fixes tag from patch 1
- add Florian's suggestions to patch 5

Changes in V3:
- introduce SoC-specific compatibles for GENET (incl. dt-binding)
- use platform_get_irq_optional for optional IRQ
- remove Fixes tag from IRQ error handling change
- move most of MDIO stuff to bcm2711.dtsi

Changes in V2:
- add 2 fixes for IRQ retrieval
- add support for missing PHY modes
- declare PHY mode RGMII RXID based on the default settings
- add alias to allow firmware append the MAC address
====================

Signed-off-by: David S. Miller <davem@davemloft.net>