V4L/DVB (6478): ir-functions use input functions, should depend on INPUT

Media ir-functions uses input_(*) functions so it should depend
on the INPUT config symbol.

drivers/built-in.o: In function `ir_input_key_event':
ir-functions.c:(.text+0x10849a): undefined reference to `input_event'
ir-functions.c:(.text+0x1084ac): undefined reference to `input_event'

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