ARM: dts: omap4: Correct the dma controller's property names

According to the Documentation/devicetree/bindings/dma/dma.txt the
dma-channels and dma-requests property should not have '#'.

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