arm64: dts: ti: k3-am62a7-sk: HACK: Reduce mailbox fifos

commit 4186fbe25a8c2f68565bd95002dc619fed256ae3 from
git://git.ti.com/ti-linux-kernel/ti-linux-kernel.git



As such each mailbox cluster in AM62A have 16 fifos. For Linux rpmsg
IPC only 2 fifos are used. The rest of the fifos could be used for
RTOS-RTOS communications.

On a suspend, mailbox driver checks for any pending outstanding
messages in the fifos and if any present returns with an error.
Currently C7x DSP is not under system suspend and it seems some
mailbox messages between DM-R5 and C7 could be present in the
fifos when Linux suspend is exercised. This is resulting in mailbox
driver suspend failure. As a HACK for now restrict the mailbox fifos
to 2, which are used for Linux IPC with remote core.

Signed-off-by: Hari Nagalla <hnagalla@ti.com>
Signed-off-by: Xulin Sun <xulin.sun@windriver.com>