firmware: ti_sci: Add RM mapping table for am654

Add the resource mapping table for AM654 SoC as defined in
http://downloads.ti.com/tisci/esd/latest/5_soc_doc/am6x/resasg_types.html


Introduce a new compatible for AM654 "ti,am654-sci" for using
this resource map table.

Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Acked-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>