staging: comedi: das800: cleanup the boardinfo

For aesthetic reasons, name the enum used for the boardinfo indexes
and change them to uppercase with the prefix BOARD_.

Add some whitespace to the boardinfo declaration and use the enum
values to clarify the table.

Tidy up the das800_probe() function and only output a dev_dbg()
message if a board model is actually probed. If the user provided
the correct boardname when attaching to this driver the message
is just added noise.

For the 'default' case when checking the proded id, output the
id_bits and return -EINVAL. It should not be assumed that unknown
boards will work with this driver.

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>