Support levels 5.0 and 5.1 in the encoder properly

The function ih264e_get_lvl_idx lacked handling of them
before, which meant that it returned index 0 (corresponding
to level 1.0) if level 5.0 or 5.1 were selected.

Change-Id: I482213e68e11fd091c72ec57a593392aa1a0a4ae
diff --git a/encoder/ih264e_utils.c b/encoder/ih264e_utils.c
index 44e4cc0..3657f33 100644
--- a/encoder/ih264e_utils.c
+++ b/encoder/ih264e_utils.c
@@ -225,6 +225,14 @@
     {
         lvl_idx = 12;
     }
+    else if (level < IH264_LEVEL_51)
+    {
+        lvl_idx = 13;
+    }
+    else
+    {
+        lvl_idx = 14;
+    }
 
     return (lvl_idx);
 }