staging: comedi: ssv_dnp: correct insn_bits result

[Part of commit f6b316bc upstream.
Split from original patch subject: "staging: comedi: ssv_dnp: use
comedi_dio_update_state()"]

Also, fix a bug where the state of the channels is returned in data[0].
The comedi core expects it to be returned in data[1].
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/staging/comedi/drivers/ssv_dnp.c

@@ -251,11 +251,11 @@ static int dnp_dio_insn_bits(struct comedi_device *dev,
 
 	/* on return, data[1] contains the value of the digital input lines. */
 	outb(PADR, CSCIR);
-	data[0] = inb(CSCDR);
+	data[1] = inb(CSCDR);
 	outb(PBDR, CSCIR);
-	data[0] += inb(CSCDR) << 8;
+	data[1] += inb(CSCDR) << 8;
 	outb(PCDR, CSCIR);
-	data[0] += ((inb(CSCDR) & 0xF0) << 12);
+	data[1] += ((inb(CSCDR) & 0xF0) << 12);
 
 	return 2;