drm/i915: Give encoders useful names

Rather than let the core generate usless encoder names, let's pass in
something that actually identifies the piece of hardware we're dealing
with.

v2: Use 'DSI %c' instead of 'MIPI %c' for DSI encoders (Jani)
v3: Use port_name() in DSI code since we have it

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1464371966-15190-7-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index d65fd94..56eb3bd 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -978,7 +978,7 @@
 			   DRM_MODE_CONNECTOR_LVDS);
 
 	drm_encoder_init(dev, &intel_encoder->base, &intel_lvds_enc_funcs,
-			 DRM_MODE_ENCODER_LVDS, NULL);
+			 DRM_MODE_ENCODER_LVDS, "LVDS");
 
 	intel_encoder->enable = intel_enable_lvds;
 	intel_encoder->pre_enable = intel_pre_enable_lvds;