soc: bcm2835: sync firmware properties with downstream

Add latest firmware property tags from the latest Raspberry Pi downstream
kernel. This is needed for the GPIO tags, so we can control the GPIO
multiplexor lines.

Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>