V4L/DVB (6480): bttv: uses input functions, should depend on INPUT

Several media drivers use input_(*) functions so they need to depend on
the INPUT config symbol.

drivers/built-in.o: In function `bttv_input_fini':
linux-2.6.24-rc1-git4/drivers/media/video/bt8xx/bttv-input.c:346: undefined reference to `input_unregister_device'
drivers/built-in.o: In function `bttv_input_init':
linux-2.6.24-rc1-git4/drivers/media/video/bt8xx/bttv-input.c:204: undefined reference to `input_allocate_device'
linux-2.6.24-rc1-git4/drivers/media/video/bt8xx/bttv-input.c:335: undefined reference to `input_free_device'
linux-2.6.24-rc1-git4/drivers/media/video/bt8xx/bttv-input.c:321: undefined reference to `input_register_device'
linux-2.6.24-rc1-git4/drivers/media/video/bt8xx/bttv-input.c:335: undefined reference to `input_free_device'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>