arm: dts: lpc32xx: add clock controller device node

NXP LPC32xx SoC has a clocking and power control unit (CPC) as a part
of system control block (SCB). CPC is supplied by two external
oscillators and it manages core and most of peripheral clocks, the
change adds SCB and CPC descriptions to shared LPC32xx dtsi file.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>