I have a netgear WNDR3700 that appears to have an off-by-four
bug in how it fills out the hti->control_chan (I configure the
AP to channel 11, it reports 15 as control_chan).

Poke a message into the kernel logs to give users a
clue as to why they are not getting the expected
channel-type or rate.
Signed-off-by: NBen Greear <greearb@candelatech.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>