stereo_dft_dec_core_switching module converted to fixed.
[x] stereo_dft_dec_core_switching module and few related sub functions updated for fixed point.
Testing:
[x] Decoder pytest: 568 failed, 1 passed, 381 skipped.
[x] MLD test: There is a deviation of more than MLD score of 5 for 19 files. However, the deviations are observed in Linux only and not in Windows. Debugging in progress.
Edited by Sandesh Venkatesh