Move QP bounding to reflect properly

Bounding of QP values was handled late and not being propagated back to the client.

Bug: 183211971
Test: VQ tests
Change-Id: Id77df74a3b2311983bf45a4a37eab7cbda6cfdbf
diff --git a/media/codec2/components/avc/C2SoftAvcEnc.h b/media/codec2/components/avc/C2SoftAvcEnc.h
index baf33e2..1fecd9e 100644
--- a/media/codec2/components/avc/C2SoftAvcEnc.h
+++ b/media/codec2/components/avc/C2SoftAvcEnc.h
@@ -99,8 +99,10 @@
 #define STRLENGTH                   500
 #define DEFAULT_CONSTRAINED_INTRA   0
 
-/** limits as specified by h264 */
-#define CODEC_QP_MIN                0
+/** limits as specified by h264
+ *  (QP_MIN==4 is actually a limitation of this SW codec, not the H.264 standard)
+ **/
+#define CODEC_QP_MIN                4
 #define CODEC_QP_MAX                51