OMAP4: hwmod data: Move the DMA structures

The merge of the DMA series on top of the already modified
omap_hwmod_data_44xx.c put the dma_system structures at
the wrong position in the file.
Re-order it properly.

Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Tested-by: G, Manjunath Kondaiah <manjugk@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>