PCI: brcmstb: Add bcm7278 register info

PCI: brcmstb: Add bcm7278 register info

Add in compatibility strings and code for three Broadcom STB chips.  Some
of the register locations, shifts, and masks are different for certain
chips, requiring the use of different constants based on of_id.

We would like to add the following at this time to the match list but we
need to wait until the end of this patchset so that everything works.

    { .compatible = "brcm,bcm7211-pcie", .data = &generic_cfg },
    { .compatible = "brcm,bcm7278-pcie", .data = &bcm7278_cfg },
    { .compatible = "brcm,bcm7216-pcie", .data = &bcm7278_cfg },
    { .compatible = "brcm,bcm7445-pcie", .data = &generic_cfg },

Link: https://lore.kernel.org/r/20200911175232.19016-4-james.quinlan@broadcom.com
Signed-off-by: Jim Quinlan <jquinlan@broadcom.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>