V4L/DVB (4267): Remove all instances of request_module("tda9887")

We should no longer try to load the tda9887 module, because it no longer
exists. The tda9887 driver has been merged into the tuner module.
This patch removes all instances of request_module("tda9887") from
the following video4linux drivers: bttv, cx88, em28xx and saa7134.

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