Unless the sponsor is a Platinum or Gold one, we use "col-lg-6" as the
CSS class of the outter <div> when printing the "Your organization
could be here<br>Be a XYZ sponsor!" text. As it turns out, the dotted
box becomes too small for the text being printed, which causes display
issues for the lower sponsorship categories. This commit makes the
"sponsor-us" <div> to always use the "col-lg-12" class, which is big
enough for the text (and, IMHO, also looks better, because the box
occupies the entire row).