Staging: comedi: Added reading of board serial number from eeprom for m-series boards

Nothing is done with it yet, eventually it will be made available to
user-space via a readable file in sysfs.

From: Frank Mori Hess <fmhess@users.sourceforge.net>
Cc: David Schleef <ds@schleef.org>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>