Report values of TMC2208 register fields in DUMP_TMC command to help in
tuning and diagnostics.
This also adds functions to refer to register fields by name for TMC drivers
and register mappings for TMC2208.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Signed-off-by: Dmitry Frolov <dmitry.frolov@gmail.com>