Low: controller: Remove CRM_CHECK in update_dc for no current DC
Since invalid is true and dc_name is NULL, we know that:
- We are the (a) DC, and
- The welcome_from node isn't us.
At that point, we might as well just log the if (AM_I_DC) message and
forget about logging the "We have no DC" message. It isn't really
relevant to the flow here.
Signed-off-by: Reid Wahl <nrwahl@protonmail.com>