convert SFX_CALLMODE constants to SfxCallMode enum class

and fix a couple of bugs in SC and SW where the call mode was
being passed to the hints parameter by accident

Change-Id: Ief805410b3f7035e012e229e77f92d5832430f58
Reviewed-on: https://gerrit.libreoffice.org/11916
Reviewed-by: Noel Grandin <noelgrandin@gmail.com>
Tested-by: Noel Grandin <noelgrandin@gmail.com>