arm64: dts: ti: k3-am65-wakeup: Add debug region to TI-SCI node

Lets add the TISCI debug region to TI-SCI region in line with TI-SCI
documentation[1]. While at it, lets rename the node to indicate the
address usage.

[1] http://downloads.ti.com/tisci/esd/latest/4_trace/trace.html

Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Tero Kristo <kristo@kernel.org>
Link: https://lore.kernel.org/r/20210510145033.7426-3-nm@ti.com