SBA decoder mono out: Big differences between BASOP and Float
# Basic info
<!--- Add commit SHA used to reproduce-->
- Float reference:
- Encoder (float): 957cd45f4d6e88fb0f52d5b1df258c1668a9c61e
- Decoder (float): 957cd45f4d6e88fb0f52d5b1df258c1668a9c61e
- Fixed point:
- Encoder (fixed): n/a
- Decoder (fixed): ca3146eb9de8185ed0247945c643267826a32a94
# Bug description
For the SBA decoder with mono output, there are still big differences between BASOP and float.
**Diff BASOP-Float** 
It seems to origin from the Mono DMX, since with EXT output the diffs get significantly smaller
# Ways to reproduce
<!--Commandline or script-->
```bash
IVAS_dec MONO 48 ltv48_FOA.wav_SBA_at_32_kbps_48kHz_in_48kHz_out_MONO_out_DTX_bandwidth_switching.192 out.wav
```
Bitstreams (incl. one bitstream w/o bandwidth switching, which has similar issues): [bitstreams.zip](/uploads/42d985d7902166403f9bf8e4b6356d36/bitstreams.zip)
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Actual diff basop vs. float with bugfixes in dec_tcx_fx

Actual diff basop vs. float

ACELP core output float at frame 6900 (MONO)

ACELP core output float at frame 6900 (EXT)

ACELP core output basop at frame 6900 (MONO)

ACELP core output basop at frame 6900 (EXT)

issue