Core coder functions integration/conversion to fixed point

[x] acelp_core_enc porting
[x] Conversion of SetTCXModeInfo() function in ivas_mdct_core_whitening_enc() call stack
[x] Fix for LTV crash - ltv-stereo at 13.2 kbps, 48kHz in, 48kHz out
[x] stereo_tcx_core_enc: Integrated writeTCXParam and writeLPCparam
[x] hq lr enc conversion in hq-core path