staging: comedi: ni_6527: rename CamelCase defines for the clear register

staging: comedi: ni_6527: rename CamelCase defines for the clear register

Rename the CamelCase defines used for the clear register.

To clarify the code a bit, add two new defines that group the bits needed
to clear the interrupts and reset the digital input deglitch filter.

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>