drm/i915: change intel_ddc_get_modes() function parameters

This one replaces original param for intel_ddc_get_modes() with
DRM connector and i2c bus adapter instead. With explicit params,
we won't require that a single driver structure must hold connector
and DDC bus reference, which ease the conversion to splitted encoder/
connector model.

It also clears up for some cases that we would steal other DDC bus
for mode probe, like VGA analog DDC probe for DVI-I. Also it fixed
a bug in old DVI-I probe handling, that failed to restore origin
analog GPIO port.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>