Duplication of VAD parameters

Bug description

Some static parameters in the VAD module are duplicated, e.g.

• active_cnt <-> active_fr_cnt_fx
• var_SID_rate_flag <-> var_SID_rate_flag_fx
• interval_SID <-> interval_SID_fx

Also, the CLDFB VAD handle is duplicated:

• hVAD_CLDFB <-> vad_st

Further, the initialization is duplicated and not consistent between EVS and IVAS modules:

• wb_vad_init_fx() <-> wb_vad_init_ivas_fx()

Only a single set of parameters/handles/functions should be used to ensure their consistency.