dt-bindings: pci: Convert iProc PCIe to YAML

Conver the iProc PCIe controller Device Tree binding to YAML now that
all DTS in arch/arm and arch/arm64 have been fixed to be compliant.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20211214035820.2984289-7-f.fainelli@gmail.com


Signed-off-by: Rob Herring <robh@kernel.org>