drm/i915: select TV format according to connector type

For integrated TV there are 3 connector types: S-VIDEO, Composite and
Component(YprPb). Those tv formats whose component flag is true should
be assigned to Component connector, others are for S-VIDEO and Composite.
The patch intends to find appropriate tv format for each connector.
In such case it will return the correct modeline to user space. Otherwise
it will return the incorrect modeline when S-video/composite is connected.

Signed-off-by: Ma Ling <ling.ma@intel.com>
reviewed-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>