DMA transaction type not given by targets

[JuanSapriza]

Currently the transaction type is assigned from the source type. This was thought this way to allow targets to be "symmetrical" and "interchangeable".

Since the DMA only supports one data size, both should necessarily be the same. If you are already going to change the targets, changing also the type sounds reasonable.

Make the type only in the transaction and not the targets to make the logic simpler and more easy to understand for the user.