drm/i915/ddi: drop unused but set variable intel_dp

Prepare for re-enabling -Wunused-but-set-variable.

The intel_dp variable has been unused since commit ef79fafe
("drm/i915: Eliminate intel_dp.regs.dp_tp_{ctl,status}").
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/66ca543b400a2048a6a84bb57a7bac8943014a96.1685119007.git.jani.nikula@intel.com

drivers/gpu/drm/i915/display/intel_ddi.c

@@ -2225,12 +2225,10 @@ static void intel_ddi_enable_fec(struct intel_encoder *encoder,
 				 const struct intel_crtc_state *crtc_state)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
-	struct intel_dp *intel_dp;
 
 	if (!crtc_state->fec_enable)
 		return;
 
-	intel_dp = enc_to_intel_dp(encoder);
 	intel_de_rmw(dev_priv, dp_tp_ctl_reg(encoder, crtc_state),
 		     0, DP_TP_CTL_FEC_ENABLE);
 }
@@ -2239,12 +2237,10 @@ static void intel_ddi_disable_fec_state(struct intel_encoder *encoder,
 					const struct intel_crtc_state *crtc_state)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
-	struct intel_dp *intel_dp;
 
 	if (!crtc_state->fec_enable)
 		return;
 
-	intel_dp = enc_to_intel_dp(encoder);
 	intel_de_rmw(dev_priv, dp_tp_ctl_reg(encoder, crtc_state),
 		     DP_TP_CTL_FEC_ENABLE, 0);
 	intel_de_posting_read(dev_priv, dp_tp_ctl_reg(encoder, crtc_state));