Make translation global motion condition consistent

Make the translation global motion condition on block size
consistent to support 4x16 and 16x4 coding block sizes.

Change-Id: I23a0d04ca6cc08e8f29055c2c37f11b6ca204fec

av1/common/blockd.h

diff --git a/av1/common/blockd.h b/av1/common/blockd.h
index 37b7c5d..c4afd0d 100644
--- a/av1/common/blockd.h
+++ b/av1/common/blockd.h
@@ -1382,7 +1382,8 @@
   if (mbmi->mode != GLOBALMV && mbmi->mode != GLOBAL_GLOBALMV) return 0;
 
 #if !GLOBAL_SUB8X8_USED
-  if (mbmi->sb_type < BLOCK_8X8) return 0;
+  if (AOMMIN(mi_size_wide[mbmi->sb_type], mi_size_high[mbmi->sb_type]) < 8)
+    return 0;
 #endif
 
   // Now check if all global motion is non translational