dr_a1: check the descriptor length before allocating p_decoded

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
dr_a1: we only need int i declared for the for loop

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
dr_a1: remove dependency on function, dvbpsi_get_bits()

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Revert "backport function 'dvbpsi_get_bits' for the dr_a1 code"

This reverts commit da432c6ff6deedd37d7b6dad629493c6cb3a3622.