staging: comedi: fix build errors caused by module_init/module_exit refactor
A couple build errors were introduced with the module_init/module_exit
refactor.
The struct comedi_driver variable was being accessed directly in the
attach and detach routines. Instead of doing this, access the variable
indirectly using the driver pointer in struct comedi_device.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Cc: Ian Abbott <abbotti@mev.co.uk> Cc: Mori Hess <fmhess@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>