Fix twelve_bit check

twelve_bit must be false if high_bitdepth is false, not the opposite.
The issue was not raised because almost all 10b AVIF files contain a
"pixi" box that libavifinfo reads before the "av1C" box.

Change-Id: I06f9d4340fd588156bcb24aa7e97cfe7f0836337
diff --git a/avifinfo.c b/avifinfo.c
index f284924..49a0725 100644
--- a/avifinfo.c
+++ b/avifinfo.c
@@ -290,7 +290,7 @@
       const int high_bitdepth = (fields & 0x40) != 0;
       const int twelve_bit = (fields & 0x20) != 0;
       const int monochrome = (fields & 0x10) != 0;
-      AVIFINFO_CHECK(twelve_bit || !high_bitdepth, kInvalid);
+      AVIFINFO_CHECK(high_bitdepth || !twelve_bit, kInvalid);
       features->num_channels = monochrome ? 1 : 3;
       features->bit_depth = high_bitdepth ? twelve_bit ? 12 : 10 : 8;
       return kFound;