staging: comedi: rti800: remove forward declaration

This forward declaration is not needed.
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>

drivers/staging/comedi/drivers/rti800.c

@@ -130,8 +130,6 @@ struct rti800_board {
 	int has_ao;
 };
 
-static irqreturn_t rti800_interrupt(int irq, void *dev);
-
 struct rti800_private {
 	enum {
 		adc_diff, adc_pseudodiff, adc_singleended