V4L/DVB (4752): DVB: Add DVB_FE_CUSTOMISE support for MT2060

Let the MT2060 be customized like most of the other DVB PLLs/front-ends. 
Also, add a missing dependency on I2C.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>