drivers: misc: gsc: add support for prescaled

Add support for Gateworks System Controller pre-scaled ADC input.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
diff --git a/drivers/misc/gsc.c b/drivers/misc/gsc.c
index bab405b..72a13ab 100644
--- a/drivers/misc/gsc.c
+++ b/drivers/misc/gsc.c
@@ -310,6 +310,7 @@
 			printf("%-8s: %d.%ldC\n", label, val / 10, abs(val % 10));
 			break;
 		case 1: /* prescaled voltage */
+		case 3:
 			if (val != 0xffff)
 				printf("%-8s: %d.%03dV\n", label, val / 1000, val % 1000);
 			break;