linux-phytec-ti

ARM: dts: AM4372: Add PRUSS1 PRU mboxes to mailbox node

Add the reference sub-mailbox nodes to communicate between MPU
and PRU0 (Mailbox User Id 1) and PRU1 (Mailbox User Id 2) remote
processor cores within the PRU-ICSS1 subsystem. The following are
the assignments of mailbox fifos between MPU and the remote PRU
cores:

            MPU Tx/PRU Rx   MPU Rx/PRU Tx
    PRU0    2               3
    PRU1    4               5

This assignment is identical to the assignment of mailboxes for
the PRU-ICSS subsystem in AM33xx. Note that no mailboxes have been
assigned to PRUSS0 as there are not enough mailboxes available
to communicate with both PRU cores on PRUSS0 - WkupM3 consumes
one mailbox.

NOTE:
These mailboxes provide an alternate communication path between
the MPU and PRU. The current default approach is to use the PRU
System Events.

Signed-off-by: Suman Anna <s-anna@ti.com>