drm/i915: drop redundant warnings on not holding dpio_lock

The lower level sideband read/write functions already do this.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dp.c

@@ -1442,8 +1442,6 @@ static void intel_pre_enable_dp(struct intel_encoder *encoder)
 		int pipe = intel_crtc->pipe;
 		u32 val;
 
-		WARN_ON(!mutex_is_locked(&dev_priv->dpio_lock));
-
 		val = intel_dpio_read(dev_priv, DPIO_DATA_LANE_A(port));
 		val = 0;
 		if (pipe)
@@ -1470,8 +1468,6 @@ static void intel_dp_pre_pll_enable(struct intel_encoder *encoder)
 	if (!IS_VALLEYVIEW(dev))
 		return;
 
-	WARN_ON(!mutex_is_locked(&dev_priv->dpio_lock));
-
 	/* Program Tx lane resets to default */
 	intel_dpio_write(dev_priv, DPIO_PCS_TX(port),
 			 DPIO_PCS_TX_LANE2_RESET |
@@ -1622,8 +1618,6 @@ static uint32_t intel_vlv_signal_levels(struct intel_dp *intel_dp)
 	uint8_t train_set = intel_dp->train_set[0];
 	int port = vlv_dport_to_channel(dport);
 
-	WARN_ON(!mutex_is_locked(&dev_priv->dpio_lock));
-
 	switch (train_set & DP_TRAIN_PRE_EMPHASIS_MASK) {
 	case DP_TRAIN_PRE_EMPHASIS_0:
 		preemph_reg_value = 0x0004000;

drivers/gpu/drm/i915/intel_hdmi.c

@@ -1018,8 +1018,6 @@ static void intel_hdmi_pre_enable(struct intel_encoder *encoder)
 	if (!IS_VALLEYVIEW(dev))
 		return;
 
-	WARN_ON(!mutex_is_locked(&dev_priv->dpio_lock));
-
 	/* Enable clock channels for this port */
 	val = intel_dpio_read(dev_priv, DPIO_DATA_LANE_A(port));
 	val = 0;
@@ -1063,8 +1061,6 @@ static void intel_hdmi_pre_pll_enable(struct intel_encoder *encoder)
 	if (!IS_VALLEYVIEW(dev))
 		return;
 
-	WARN_ON(!mutex_is_locked(&dev_priv->dpio_lock));
-
 	/* Program Tx lane resets to default */
 	intel_dpio_write(dev_priv, DPIO_PCS_TX(port),
 			 DPIO_PCS_TX_LANE2_RESET |