drm/i915: Drop pointless i830 PIPECONF read

Reading the PIPECONF enable bit out from the hardware
in i9xx_set_pipeconf() on i830 is pointless as the bit should
always be set since we keep both pipes constantly running on
i830. Drop the pointless read and just always keep the bit set.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220202111616.1579-4-ville.syrjala@linux.intel.comReviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>

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

@@ -3158,13 +3158,11 @@ static void i9xx_set_pipeconf(const struct intel_crtc_state *crtc_state)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
 	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
-	u32 pipeconf;
-
-	pipeconf = 0;
+	u32 pipeconf = 0;
 
 	/* we keep both pipes enabled on 830 */
 	if (IS_I830(dev_priv))
-		pipeconf |= intel_de_read(dev_priv, PIPECONF(crtc->pipe)) & PIPECONF_ENABLE;
+		pipeconf |= PIPECONF_ENABLE;
 
 	if (crtc_state->double_wide)
 		pipeconf |= PIPECONF_DOUBLE_WIDE;