ARM: dts: mmp2: Add #power-domain-cells to /clocks

The power management unit, described by the soc_clocks node, controls the
power to the peripherals by the means of power domains with a single
cell -- the domain number.

Link: https://lore.kernel.org/r/20200718205019.184927-4-lkundrak@v3.sk


Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>