Try to force the PHY clock buffer enables to make the clock routing
work.

v2: Fix the pipe B case to actually enable CH0 clock buffers
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>