Modify enable_auto_alt_ref range check

Modified enable_auto_alt_ref range check because enable_auto_alt_ref = 2
was already removed.

Change-Id: I123324ba024d0b54dd72224ae82e0f941f869897
diff --git a/av1/av1_cx_iface.c b/av1/av1_cx_iface.c
index 6ae7fba..fe025fd 100644
--- a/av1/av1_cx_iface.c
+++ b/av1/av1_cx_iface.c
@@ -286,7 +286,7 @@
         "or kf_max_dist instead.");
 
   RANGE_CHECK_HI(extra_cfg, motion_vector_unit_test, 2);
-  RANGE_CHECK_HI(extra_cfg, enable_auto_alt_ref, 2);
+  RANGE_CHECK_HI(extra_cfg, enable_auto_alt_ref, 1);
   RANGE_CHECK_HI(extra_cfg, enable_auto_bwd_ref, 2);
   RANGE_CHECK(extra_cfg, cpu_used, 0, 8);
   RANGE_CHECK_HI(extra_cfg, noise_sensitivity, 6);