[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>