soc/intel/tigerlake: Add enum for DdiPortXConfig

Add an enum for `DdiPortXConfig` devicetree options. Note that setting
these options to zero does not disable the corresponding DDI port, but
instead indicates that no LFP (Local Flat Panel, i.e. internal LCD) is
connected to it.

Change-Id: I9ea10141e51bf29ea44199dcd1b55b63ec771c0a
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64047
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Tim Crawford <tcrawford@system76.com>

src/soc/intel/tigerlake/chip.h

@@ -92,6 +92,12 @@ enum slew_rate {
 	SLEW_FAST_16
 };
 
+enum ddi_port_config {
+	DDI_PORT_CFG_NO_LFP	= 0,
+	DDI_PORT_CFG_EDP	= 1,
+	DDI_PORT_CFG_MIPI_DSI	= 2,
+};
+
 struct soc_intel_tigerlake_config {
 
 	/* Common struct containing soc config data required by common code */
@@ -367,13 +373,9 @@ struct soc_intel_tigerlake_config {
 	 */
 	uint8_t gpio_pm[TOTAL_GPIO_COMM];
 
-	/* DP config */
-	/*
-	 * Port config
-	 * 0:Disabled, 1:eDP, 2:MIPI DSI
-	 */
-	uint8_t DdiPortAConfig;
-	uint8_t DdiPortBConfig;
+	/* DDI port config */
+	enum ddi_port_config DdiPortAConfig;
+	enum ddi_port_config DdiPortBConfig;
 
 	/* Enable(1)/Disable(0) HPD */
 	uint8_t DdiPortAHpd;