staging: comedi: addi_eeprom: add defines for the 93c76 eeprom bits

Define the magic values used for the clock, chip-select, data out,
and data in signals to the 93c76 eeprom.

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