siren: Fix floating point invalid operation

Mix of single and double precision leads to zero-by-zero divide
for upper 64-bit of the xmm register, even though they are not
used.
5 jobs for siren-fpsignal in 1 minute and 45 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Manifest
passed manifest #44250

00:00:20

 
  Build
passed build fedora x86_64 #44259

00:01:25

failed build fedora x86_64 #44258

00:01:30

failed build fedora x86_64 #44254

00:01:29

canceled build fedora x86_64 #44251

00:06:36