Clearer av1C twelve_bit check

Change-Id: I5ba1780d1459a51a6501be5d8dec8c0a1277d5a7

avifinfo.c

diff --git a/avifinfo.c b/avifinfo.c
index 49a0725..62ace0c 100644
--- a/avifinfo.c
+++ b/avifinfo.c
@@ -290,7 +290,9 @@
       const int high_bitdepth = (fields & 0x40) != 0;
       const int twelve_bit = (fields & 0x20) != 0;
       const int monochrome = (fields & 0x10) != 0;
-      AVIFINFO_CHECK(high_bitdepth || !twelve_bit, kInvalid);
+      if (twelve_bit) {
+        AVIFINFO_CHECK(high_bitdepth, kInvalid);
+      }
       features->num_channels = monochrome ? 1 : 3;
       features->bit_depth = high_bitdepth ? twelve_bit ? 12 : 10 : 8;
       return kFound;