arm64: dts: ti: phycore-am64: Add R5F DMA Region and Mailboxes

Communication between the R5F subsystem and Linux takes place using DMA
memory regions and mailboxes. Here we add DT nodes for the memory
regions and mailboxes to facilitate communication between the R5
clusters and Linux as remoteproc will fail to start if no memory
regions or mailboxes are provided.

Fixes: c48ac0ef ("arm64: dts: ti: Add support for phyBOARD-Electra-AM642")
Signed-off-by: Garrett Giordano <ggiordano@phytec.com>
Reviewed-by: Wadim Egorov <w.egorov@phytec.de>
Link: https://lore.kernel.org/r/20231204212304.1736306-1-ggiordano@phytec.com


Signed-off-by: Nishanth Menon <nm@ti.com>