dt-bindings: arm: bcm: Convert BCM2835 firmware binding to YAML

Convert the Raspberry Pi BCM2835 firmware binding document to YAML.
Verified with dt_binding_check and dtbs_check.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/5bc0b9be8544b07300fccab4d4f26e5e5d8e62b2.1592210452.git-series.maxime@cerno.tech


Signed-off-by: Stephen Boyd <sboyd@kernel.org>