drm/radeon: fix correctness of irq_enabled check for radeon.

This check was introduced with the logic the wrong way around.

Fixes regression: http://bugzilla.kernel.org/show_bug.cgi?id=12216

Tested-by: François Valenduc <francois.valenduc@tvcablenet.be>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/radeon_irq.c

@@ -44,7 +44,7 @@ void radeon_irq_set_state(struct drm_device *dev, u32 mask, int state)
 	else
 		dev_priv->irq_enable_reg &= ~mask;
 
-	if (!dev->irq_enabled)
+	if (dev->irq_enabled)
 		RADEON_WRITE(RADEON_GEN_INT_CNTL, dev_priv->irq_enable_reg);
 }
 
@@ -57,7 +57,7 @@ static void r500_vbl_irq_set_state(struct drm_device *dev, u32 mask, int state)
 	else
 		dev_priv->r500_disp_irq_reg &= ~mask;
 
-	if (!dev->irq_enabled)
+	if (dev->irq_enabled)
 		RADEON_WRITE(R500_DxMODE_INT_MASK, dev_priv->r500_disp_irq_reg);
 }