[media] atmel-isc: fix off-by-one comparison and out of bounds read issue

The are only HIST_ENTRIES worth of entries in  hist_entry however the
for-loop is iterating one too many times leasing to a read access off
the end off the array ctrls->hist_entry.  Fix this by iterating by
the correct number of times.

Detected by CoverityScan, CID#1415279 ("Out-of-bounds read")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Hans Verkuil <hansverk@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/atmel/atmel-isc.c

@@ -1298,7 +1298,7 @@ static void isc_hist_count(struct isc_device *isc)
 	regmap_bulk_read(regmap, ISC_HIS_ENTRY, hist_entry, HIST_ENTRIES);
 
 	*hist_count = 0;
-	for (i = 0; i <= HIST_ENTRIES; i++)
+	for (i = 0; i < HIST_ENTRIES; i++)
 		*hist_count += i * (*hist_entry++);
 }