staging: comedi: rtd520: remove 'intCount' from the private data

This variable is cleared when an ai command is initiated and then
incremented with each interrupt. Other than that it's never used.
Just remove it.

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>