drm/i915/dp: Reset the link params on HPD/connected boot/resume

drm/i915/dp: Reset the link params on HPD/connected boot/resume

The max link parameters should be set/reset only on HPD or
connected boot case or on system resume.

Add a flag reset_link_params to intel_dp to decide when
to reset the max link parameters. This prevents the parameters
from getting reset/overwritten through all other
connector->funcs->detect() calls. This is important when link
training fails and the max link params are modified to the
lower fallback values.

Cc: Ville Syrjala <[email protected]>
Reviewed-by: Ville Syrjälä <[email protected]>
Signed-off-by: Manasi Navare <[email protected]>
Signed-off-by: Jani Nikula <[email protected]>
Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]