V4L/DVB (3970): Cx88-blackbird: use firmware api commands defined in cx2341x.h

This patch removes all of the BLACKBIRD_API #define's, instead
using the equivalent CX2341X_ENC #define's in cx2341x.h

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>