V4L/DVB (5260): Cx88-blackbird: allow usage of both 376836 and 262144 sized firmware images

This updates the cx88-blackbird driver to be able to use the new cx23416
firmware image released by Hauppauge Computer Works, while retaining
compatibility with the older firmware images.
cx2341x firmware can be downloaded at: http://dl.ivtvdriver.org/ivtv/firmware/

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