ARM: dts: dra74x: convert IOMMUs to use ti-sysc

Convert dra74x IOMMUs to use ti-sysc instead of legacy omap-hwmod based
implementation. Enable the IOMMUs also while doing this.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>