drm/i915: move infoframe setting to after pll enable v3

Needs to happen after clock is running or it doesn't behave correctly.

v2: fix subject (Ville)
    make it clearer that this occurs in pre_enable (Paulo)
    misc bikesheds (Paulo)

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>