Enable UART, unlock GPIO, set clksrcusage for GPU

src/mainboard/system76/cfl-h/Kconfig

@@ -11,6 +11,7 @@ config BOARD_SPECIFIC_OPTIONS
 	select HAVE_ACPI_TABLES
 	select HAVE_SMI_HANDLER
 	select INTEL_GMA_HAVE_VBT
+	select INTEL_LPSS_UART_FOR_CONSOLE
 #	select MAINBOARD_HAS_SPI_TPM_CR50
 #	select MAINBOARD_HAS_TPM2
 	select NO_UART_ON_SUPERIO
@@ -61,10 +62,9 @@ config ONBOARD_VGA_IS_PRIMARY
 	bool
 	default y
 
-# This causes UEFI to hang
-#config UART_FOR_CONSOLE
-#	int
-#	default 2
+config UART_FOR_CONSOLE
+	int
+	default 2
 
 config MAX_CPUS
 	int

src/mainboard/system76/cfl-h/devicetree.cb

@@ -126,6 +126,7 @@ chip soc/intel/cannonlake
 	register "PcieClkSrcClkReq[11]" = "11"
 
 	# PCI Express on CPU x8, Clock 8 (GPU)
+	register "PcieClkSrcUsage[8]" = "0x40"
 	register "PcieClkSrcClkReq[8]" = "8"
 
 	# Misc
@@ -144,6 +145,9 @@ chip soc/intel/cannonlake
 	# Thermal
 	register "tcc_offset" = "2"
 
+	# Unlock GPIO pads
+	register "PchUnlockGpioPads" = "1"
+
 	# Serial IRQ Continuous
 	register "SerialIrqConfigSirqMode" = "1"