Adding RTCD for DNN code

Makefile.am

celt/x86/x86cpu.h

dnn/dred_rdovae_dec.c

dnn/dred_rdovae_dec.h

dnn/dred_rdovae_enc.c

dnn/dred_rdovae_enc.h

dnn/dump_data.c

dnn/fargan.c

dnn/lpcnet.h

dnn/lpcnet_demo.c

dnn/lpcnet_enc.c

dnn/lpcnet_plc.c

dnn/lpcnet_private.h

dnn/nnet.c

dnn/nnet.h

dnn/nnet_arch.h

dnn/nnet_default.c

dnn/pitchdnn.c

dnn/pitchdnn.h

dnn/vec_avx.h