ARM: dts: brcmstb: un-hexify clock frequency

This value makes much more sense in decimal.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Acked-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>