ARM: dts: arm: Update ICST clock nodes 'reg' and node names

Add a 'reg' entry for ICST clock nodes on the Arm Ltd platforms. The 'reg'
entry is the VCO register address. With this, the node name can be updated
to use a generic node name, 'clock-controller', and a unit-address.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20211024232239.211822-1-linus.walleij@linaro.org'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>