V4L/DVB (4387): Add Kconfig infrastructure for dvb_attach

Allow it to be en/disabled
Disable it in < 2.6.17 due to symbol_xxx() bug

Signed-off-by: Andrew de Quincey <adq_dvb@lidskialf.net>
Acked-by: Michael Krufky <mkrufky@linuxtv.org>
Acked-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>