ARM: dts: Add cppi41 support for dm816x MUSB

Looks like we have cppi41 on dm816x just like on am335x.

Cc: Bin Liu <binmlist@gmail.com>
Cc: Brian Hutchinson <b.hutchman@gmail.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Matthijs van Duin <matthijsvanduin@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>