validate_img: add error msg for validate_hbd_input failure

Change-Id: Ie9534502ead1d14decaaafb17da9d6fa032d6519
(cherry picked from commit 1148881ff180a23cfbc4ed3ee0f925f2873a7558)

av1/av1_cx_iface.c

diff --git a/av1/av1_cx_iface.c b/av1/av1_cx_iface.c
index 44482f5..143a4bd 100644
--- a/av1/av1_cx_iface.c
+++ b/av1/av1_cx_iface.c
@@ -1035,7 +1035,7 @@
       for (unsigned int i = 0; i < ph; ++i) {
         for (unsigned int j = 0; j < pw; ++j) {
           if (src[j] >= max_val) {
-            return AOM_CODEC_INVALID_PARAM;
+            ERROR("Input pixel value out of range for encoder bit depth");
           }
         }
         src += stride;