I suspect this issue may be due to the following commit, which got reverted later in 3.13:
commit a6c2390cd6d2083d27a2359658e08f2d3df375ac Author: Matthew Garrett <email address hidden> AuthorDate: Fri Jun 1 12:46:56 2012 -0400
dell-laptop: Remove rfkill code
I suspect this issue may be due to the following commit, which got reverted later in 3.13:
commit a6c2390cd6d2083 d27a2359658e08f 2d3df375ac
Author: Matthew Garrett <email address hidden>
AuthorDate: Fri Jun 1 12:46:56 2012 -0400
dell-laptop: Remove rfkill code