Stereo path encoder functions converted to fixed

[x] Stereo TCX Core Encoder & sub-functions: stereo_tcx_init_enc, InitTnsConfigs, getCoreSamplerateMode2, SetAllowTnsOnWhite, getIgfPresent, sr2fscale, tcxlpc_get_cdk, writeTCXMode, writeTCXWindowing. stereo_tcx_core_enc conversion - partial done.
[x] Functions in ivas_sns_enc.c converted to fixed: sns_1st_cod, sns_2st_cod, sns_avq_cod, sns_avq_cod_stereo
[x] Functions in ivas_stereo_td_analysis.c converted to fixed: Comp_diff_lt_corr, Get_LR_rms, Get_corr_n, Get_dt_lt_ener, limit_idx_Dwnmix, stereo_smooth_LR_transition, stereo_tdm_ener_analysis_SM