tree: Use eist_enable as bool for newly merged files

Change-Id: Icc01852dc5bd04cfa151e8fa7c5bcc160ed978c6
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/84156
Reviewed-by: Sean Rhodes <sean@starlabs.systems>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/protectli/vault_adl_p/devicetree.cb

@@ -1,7 +1,7 @@
 chip soc/intel/alderlake
 	# FSP configuration
 
-	register "eist_enable" = "1"
+	register "eist_enable" = "true"
 
 	# Sagv Configuration
 	register "sagv" = "SaGv_Enabled"

src/mainboard/starlabs/starlite_adl/variants/mk_v/devicetree.cb

@@ -13,7 +13,7 @@ chip soc/intel/alderlake
 	register "sagv"				= "SaGv_Enabled"
 
 	# FSP Silicon
-	register "eist_enable"			= "1"
+	register "eist_enable"			= "true"
 	register "cnvi_bt_core"			= "true"
 	register "cnvi_bt_audio_offload"	= "true"
 

src/mainboard/system76/mtl/devicetree.cb

@@ -11,7 +11,7 @@ chip soc/intel/meteorlake
 	}"
 
 	# Enable Enhanced Intel SpeedStep
-	register "eist_enable" = "1"
+	register "eist_enable" = "true"
 
 	# Thermal
 	register "tcc_offset" = "8"