STM32L0 uses the same DMA peripheral as STM32F0, F1, L1 and others
with some differences. Those are mostly in the number of supported
controllers and channels.
This patch enables the basic support with no attempt to only expose
the available controllers / channels.
For more information see the ST Application Note AN2548.
Signed-off-by: Martin Sivak <mars@montik.net>
