libavcenc: model CBR-NLDRC as CBR mode with out frame drops

In frame drop mode, the stream generated is non-compliant.
For now disable frame drop mode.

Bug: oss-fuzz-61202
Bug: oss-fuzz-59598
Test: ./avc_enc_fuzzer

Change-Id: Ifed950082ae2c6e70d6a7da4547b6ffeb44cf759

encoder/ih264e_rate_control.c

@@ -596,7 +596,9 @@ WORD32 ih264e_rc_post_enc(void * ps_rate_control_api,
     pi4_is_post_encode_skip[0]= 0;
 
     /* For NLDRC, get the buffer status for stuffing or skipping */
-    if (irc_get_rc_type(ps_rate_control_api) == CBR_NLDRC)
+    /* Default NLDRC to CBR with no frame drops. */
+    /* FIX ME: In frame drop mode, the bitstream generated is non-compliant */
+    if (0 && irc_get_rc_type(ps_rate_control_api) == CBR_NLDRC)
     {
         WORD32 i4_get_num_bit_to_prevent_vbv_overflow;
         UWORD8 u1_enc_buf_overflow,u1_enc_buf_underflow;