PCI: brcmstb: Add control of rescal reset

Some STB chips have a special purpose reset controller named RESCAL (reset
calibration).  The PCIe HW can now control RESCAL to start and stop its
operation.  On probe(), the RESCAL is deasserted and the driver goes
through the sequence of setting registers and reading status in order to
start the internal PHY that is required for the PCIe.

Link: https://lore.kernel.org/r/20200911175232.19016-7-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>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>