staging: comedi: amplc_dio200.h: remove struct dio200_layout definition

This struct is used to provide part of the boardinfo data. Using the extra
indirection does not provide any additional clarity to the driver.

Absorb the members from dio200_layout into dio200_board and remove the
extra 'layout' indirection.

For aesthetics, rename all the local variables used for the boardinfo
pointer to 'board'.

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>