ARM: dts: Revert am335x mcasp ti-sysc changes

Without this McASP FIFO would constantly underflow. EDMA
test via dmatest works though.

Let's revert the change for now until we know the root cause.

Reported-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>