dt-bindings: PCI: Add bindings for more Brcmstb chips

dt-bindings: PCI: Add bindings for more Brcmstb chips

- Add compatible strings for three more Broadcom STB chips: 7278, 7216,
  7211 (STB version of RPi4).
- Add new property 'brcm,scb-sizes'.
- Add new property 'resets'.
- Add new property 'reset-names' for 7216 only.
- Allow 'ranges' and 'dma-ranges' to have more than one item and update
  the example to show this.

Link: https://lore.kernel.org/r/20200911175232.19016-3-james.quinlan@broadcom.com
Signed-off-by: Jim Quinlan <jquinlan@broadcom.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>