For RISC-V and Cortex-M-not-3, triples are known and have worked in some
configuration, but do not work at the moment and stay disabled until the
reference platforms (native, M3) have been established well.
Currently implementations of the MTD api are selecting the module,
this makes it easy for default backends to be selected. But the
correct modeling is simply selecting the MTD api and then selecting
a backend. BOARDs providing one of the backends can expose this and
then that backend can be selected by default.
There is also currently nothing preventing from using the MTD api
with no backend since a mock backend can easily be provided as is
done in all mtd tests.
Native CAN device was not properly ported to periph_can interface.
This commit fixes this by renaming all needed structures and files so
auto_init_can can initialize the native device. FEATURES_PROVIDED is
also updated for native.
