- Add DRM_GET_PRIV_WITH_RETURN macro. This can be used in shared code to

    get the drm_file_t * based on the filp passed in ioctl handlers.
- Use this macro on BSD for simplification and improve its error reporting.
    Make failure to find the drm_file_t * print as an error, not debug.
    This failure may be part of the problem with KDE.
- Make debug and error print macros include the pid on BSD.