Display and DCAN drivers use syscon regmap to access some registers
in the CORE control area. Add the syscon regmap node for this
area.

Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Nishanth Menon <nm@ti.com>
Signed-off-by: NRoger Quadros <rogerq@ti.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>