arm64: dts: ti: k3-am62-verdin: Add missing cfg for TI IPC Firmware

arm64: dts: ti: k3-am62-verdin: Add missing cfg for TI IPC Firmware

The wkup_r5fss0_core0_memory_region is used to store the text/data
sections of the Device Manager (DM) firmware itself and is necessary for
platform boot. Whereas the wkup_r5fss0_core0_dma_memory_region is used
for allocating the Virtio buffers needed for IPC with the DM core which
could be optional. The labels were incorrectly used in the
k3-am62-verdin.dtsi file. Correct the firmware memory region label.

Currently, only mailbox node is enabled with FIFO assignment for a
single M4F remote core. However, there are no users of the enabled
mailboxes. Add the missing carveouts for WKUP R5F and MCU M4F remote
processors, and enable those by associating to the above carveout and
mailboxes. This config aligns with other AM62 boards and can be
refactored out later.

Signed-off-by: Beleswar Padhi <b-padhi@ti.com>
Tested-by: Hiago De Franco <hiago.franco@toradex.com> # Verdin AM62
Acked-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Link: https://patch.msgid.link/20250908142826.1828676-17-b-padhi@ti.com
Signed-off-by: Nishanth Menon <nm@ti.com>