staging: comedi: addi_apci_3xxx: prefer using the BIT macro

As suggested by checkpatch.pl, use the BIT macro to define the
register bits.
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>

drivers/staging/comedi/drivers/addi_apci_3xxx.c

@@ -27,9 +27,9 @@
 
 #include "../comedi_pci.h"
 
-#define CONV_UNIT_NS		(1 << 0)
-#define CONV_UNIT_US		(1 << 1)
-#define CONV_UNIT_MS		(1 << 2)
+#define CONV_UNIT_NS		BIT(0)
+#define CONV_UNIT_US		BIT(1)
+#define CONV_UNIT_MS		BIT(2)
 
 static const struct comedi_lrange apci3xxx_ai_range = {
 	8, {