Update and re-enable SILK SSE4.1 optimisations

silk/NSQ.c

silk/NSQ_del_dec.c

silk/SigProc_FIX.h

silk/VQ_WMat_EC.c

silk/fixed/burg_modified_FIX.c

silk/fixed/vector_ops_FIX.c

silk/fixed/x86/burg_modified_FIX_sse4_1.c

silk/fixed/x86/prefilter_FIX_sse.c

silk/fixed/x86/vector_ops_FIX_sse4_1.c

silk/main.h

silk/x86/NSQ_del_dec_sse4_1.c

silk/x86/NSQ_sse4_1.c

silk/x86/SigProc_FIX_sse.h

silk/x86/VAD_sse4_1.c

silk/x86/VQ_WMat_EC_sse4_1.c

silk/x86/main_sse.h

silk/x86/x86_silk_map.c