staging: comedi: das16: remove 'i8254_offset' from boardinfo

All the boards supported by this driver have an 8254 timer at offset
0x0c. Remove this unused information from the boardinfo.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>