In the case of OF device tree, the firmware information is attached to
the BGX device structure in the standard manner, so use the firmware
iterators and accessors where possible.

Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>