Update header filenames in actual source and header files, remove build
helpers which allowed to build unmodified files after rename.

The defines
  __CTU_CAN_FD_CAN_FD_REGISTER_MAP__ in ctucanfd_regs.h
and
  __CTU_CAN_FD_CAN_FD_FRAME_FORMAT__ in ctucanfd_frame.h

cannot be updated because update causes inconsistency with files
generated by scripts/update_reg_map and subsequent fail in Gitlab
pipelines checking for Vivado component and header files match
and marks branch as unmergeable.

Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>