ec/starlabs/merlin: Add a "off" mode for the power LED

Users have requested to be able to disable the power LED, so add
this as an option.

Change-Id: I74da148c7891ab3dd5e5b692239670c9937ab302
Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88890
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/ec/starlabs/merlin/cfr.h

@@ -109,6 +109,7 @@ static const struct sm_object power_led = SM_DECLARE_ENUM({
 	.values		= (const struct sm_enum_value[]) {
 				{ "Normal",		0		},
 				{ "Reduced",		1		},
+				{ "Off",		2		},
 				SM_ENUM_VALUE_END,
 	},
 });

src/ec/starlabs/merlin/ec.h

@@ -111,6 +111,7 @@
 /* Power LED Brightness */
 #define LED_NORMAL		0x00
 #define LED_REDUCED		0x01
+#define LED_OFF			0x02
 
 uint16_t ec_get_version(void);
 

src/ec/starlabs/merlin/ite.c

@@ -337,13 +337,14 @@ static void merlin_init(struct device *dev)
 	 *
 	 * Setting:	power_led
 	 *
-	 * Values:	0, 1
+	 * Values:	0, 1, 2
 	 * Default:	0
 	 *
 	 */
 	const uint8_t power_led[] = {
 		LED_NORMAL,
-		LED_REDUCED
+		LED_REDUCED,
+		LED_OFF
 	};
 
 	if (CONFIG(EC_STARLABS_POWER_LED))