arm64: dts: Update Stingray clock DT nodes

Update clock output names in the Stingray clock DT nodes so they match
the binding document and the latest ASIC datasheet. Also add entries
for LCPLL2

Signed-off-by: Pramod Kumar <pramod.kumar@broadcom.com>
Signed-off-by: Ray Jui <ray.jui@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>