fdo#70797 fix incorrect argument handling of CHISQ.DIST

Change-Id: I6187aa673034e6dc18f48f7b6b7ac88989ab55ec
Reviewed-on: https://gerrit.libreoffice.org/6914
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Eike Rathke <erack@redhat.com>