ARM: dts: omap24xx: add minimal l4 bus layout with control module support

This patch creates an l4 / l4-wkup interconnects for omap2420 / omap2430
SoCs, and moves some of the generic peripherals under it. System control
module nodes are moved under this new interconnect also, and the SCM
clock layout is changed to use the new SCM node as the clock provider.

Signed-off-by: Tero Kristo <t-kristo@ti.com>