Diseqc fix (incomplete)
linuxdvb: fix diseqc committed switch setting

Added new LNB callback for getting the hi/lo band setting. Minor correction
to repeat sending as well.
First committed diseqc message was being sent as a 'retransmition frame' (frame byte=E1) and the 'first frame' message (frame byte=E0) was being sent multiple times if the number of diseqc restransmitions was > 0.