Warning about pointer comparison in ivas_mdct_core_reconstruct()

The following warning is raised while compiling on Debian 12 (gcc (Debian 12.2.0-14) 12.2.0):

lib_dec/ivas_mdct_core_dec.c: In function ‘ivas_mdct_core_reconstruct’:
lib_dec/ivas_mdct_core_dec.c:946:14: warning: the comparison will always evaluate as ‘true’ for the pointer operand in ‘signal_outFB + (sizetype)((long unsigned int)ch * 4800)’ must not be NULL [-Waddress]
  946 |         if ( signal_outFB[ch] )
      |              ^~~~~~~~~~~~

https://forge.3gpp.org/rep/ivas-codec-pc/ivas-codec/-/blob/main/lib_dec/ivas_mdct_core_dec.c#L946-949

@kiene please reassign if needed.