Improve WMOPS performance of IGF_getWhiteSpectralData_ivas()

Basic info

IGF_getWhiteSpectralData_ivas() inside lib_dec/igf_dec_fx.c has a windowing sum implementation which can be rearranged.

• Float reference:
  • Encoder (float):
  • Decoder (float):
• Fixed point:
  • Encoder (fixed):
  • Decoder (fixed):

Bug description

Ways to reproduce

Box folder: ...\Box_EXTERNAL_IVAS_BASOP_VERIFICATION\issues\issue-xxxx