ARM: dts: dra7: Add scm_conf@1c04 node

This region contains CTRL_CORE_SMA_SW2..9 registers which
are not specific to any domain and can be reasonably
accessed via syscon driver.

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