dma: omap: check dma channel data_type

dma: omap: check dma channel data_type

When setting dma channel 'data_type', if (value & 3) == 3,
the set 'data_type' is said to be bad. This also leads to an
OOB access in 'omap_dma_transfer_generic', while doing
cpu_physical_memory_r/w operations. Add check to avoid it.

Reported-by: Jiang Xin <[email protected]>
Signed-off-by: Prasad J Pandit <[email protected]>
Message-id: 20170127120528[email protected]
Reviewed-by: Peter Maydell <[email protected]>
Signed-off-by: Peter Maydell <[email protected]>