gpu: host1x: Fix potential out-of-bounds access

The check for valid syncpoint IDs is off by one. While at it, rewrite
the check to make it more easily understandable.
Signed-off-by: NThierry Reding <treding@nvidia.com>

drivers/gpu/host1x/syncpt.c

@@ -484,7 +484,7 @@ unsigned int host1x_syncpt_nb_mlocks(struct host1x *host)
 
 struct host1x_syncpt *host1x_syncpt_get(struct host1x *host, unsigned int id)
 {
-	if (host->info->nb_pts < id)
+	if (id >= host->info->nb_pts)
 		return NULL;
 
 	return host->syncpt + id;