ARM: dts: berlin: add scu and chipctrl device nodes for BG2/BG2Q

This adds scu and general purpose registers device nodes required for
SMP on Berlin BG2 and BG2Q SoCs. The secondary CPUs will pick their jump
address from general purpose (SW generic) register 1.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Acked-by: Jisheng Zhang <jszhang@marvell.com>
Tested-by: Antoine Tenart <antoine.tenart@free-electrons.com>