drm/i915: Drop the nop intel_update_watermarks() call from haswell_crtc_enable()

drm/i915: Drop the nop intel_update_watermarks() call from haswell_crtc_enable()

HSW+ all use the .initial_watermarks() hook, so there's no point in
calling intel_update_watermarks() from HSW+ specific code. We'll still
hang on to the .initial_watermarks NULL check since theoretically if the
memory latencies are not populated we would not populate the function
pointer either.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1480354637-14209-2-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>