sfc: fix an off-by-one compare on an array size

encap_type should be checked to see if it is greater or equal to
the size of array map to fix an off-by-one array size check. This
fixes an array overrun read as detected by static analysis by
CoverityScan, CID#1398883 ("Out-of-bounds-read")

Fixes: 9b41080125176841e ("sfc: insert catch-all filters for encapsulated traffic")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/ef10.c

@@ -5080,7 +5080,7 @@ static int efx_ef10_filter_insert_def(struct efx_nic *efx,
 
 		/* quick bounds check (BCAST result impossible) */
 		BUILD_BUG_ON(EFX_EF10_BCAST != 0);
-		if (encap_type > ARRAY_SIZE(map) || map[encap_type] == 0) {
+		if (encap_type >= ARRAY_SIZE(map) || map[encap_type] == 0) {
 			WARN_ON(1);
 			return -EINVAL;
 		}