drm/i915/icl: Ungate ddi clocks before IO enable

IO enable sequencing needs ddi clocks enabled.
These clocks will be gated at a later point in
the enable sequence.

v2: Fix the commit header (Uma)
v3: Remove the redundant read (Ville)

Fixes: 949fc52a ("drm/i915/icl: add pll mapping for DSI")
Signed-off-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1553513202-13863-1-git-send-email-vandita.kulkarni@intel.com

drivers/gpu/drm/i915/icl_dsi.c

@@ -602,6 +602,12 @@ static void gen11_dsi_map_pll(struct intel_encoder *encoder,
 		val |= DPCLKA_CFGCR0_DDI_CLK_SEL(pll->info->id, port);
 	}
 	I915_WRITE(DPCLKA_CFGCR0_ICL, val);
+
+	for_each_dsi_port(port, intel_dsi->ports) {
+		val &= ~DPCLKA_CFGCR0_DDI_CLK_OFF(port);
+	}
+	I915_WRITE(DPCLKA_CFGCR0_ICL, val);
+
 	POSTING_READ(DPCLKA_CFGCR0_ICL);
 
 	mutex_unlock(&dev_priv->dpll_lock);