b4f29035ce6ee12949df1227ee463340ea8e8571 adapted the can_linux module to
the periph_can interface. This is a cleanup of some things that stayed
behind. Here the makefile is removed, the references to can_linux in the
dependency resolution and configuration Makefile are changed to the
standard periph_can, and the startup code is adapted.
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.