V4L/DVB (3335): Fix in-kernel build

- remove tuner.ko build dependency on xc3028.o , which will be added again later.
- fix the following build error when using the "make kernel-links" build method to
  symlink the latest code from the v4l-dvb repository into the kernel source:
drivers/media/video/xc3028.c:31:20: em28xx.h: No such file or directory
drivers/media/video/xc3028.c: In function `xc3028_init':
drivers/media/video/xc3028.c:120: error: dereferencing pointer to incomplete type
drivers/media/video/xc3028.c:121: error: dereferencing pointer to incomplete type
drivers/media/video/xc3028.c:139: error: dereferencing pointer to incomplete type
drivers/media/video/xc3028.c:140: error: dereferencing pointer to incomplete type
make[3]: *** [drivers/media/video/xc3028.o] Error 1

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