soc/intel/skylake: Initialize UART based on CONFIG_UART_DEBUG

Current implementation checks for CONFIG_BOOTBLOCK_CONSOLE and then
initializes UART. If only CONFIG_BOOTBLOCK_CONSOLE
is enabled without enabling CONFIG_UART_DEBUG, there are
compilation issues. This is the case when using SIO UART for Skylake
DT platform. Hence initialize UART when CONFIG_UART_DEBUG is enabled
and not based on CONFIG_BOOTBLOCK_CONSOLE.

Also move BOOTBLOCK_CONSOLE out from UART_DEBUG to CPU_SPECIFIC_OPTIONS
as part of the fix needed.

Change-Id: Id422a55a68d64a06fc874bddca46b0ef5be6d596
Signed-off-by: Teo Boon Tiong <boon.tiong.teo@intel.com>
Reviewed-on: https://review.coreboot.org/17349
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/intel/skylake/Kconfig

@@ -13,6 +13,7 @@ config CPU_SPECIFIC_OPTIONS
 	select ARCH_ROMSTAGE_X86_32
 	select ARCH_VERSTAGE_X86_32
 	select ACPI_NHLT
+	select BOOTBLOCK_CONSOLE
 	select BOOT_DEVICE_SPI_FLASH_RW_NOMMAP_EARLY if BOOT_DEVICE_SPI_FLASH
 	select BOOT_DEVICE_SUPPORTS_WRITES
 	select CACHE_MRC_SETTINGS
@@ -182,7 +183,6 @@ config VGA_BIOS_ID
 config UART_DEBUG
 	bool "Enable UART debug port."
 	default n
-	select BOOTBLOCK_CONSOLE
 	select CONSOLE_SERIAL
 	select DRIVERS_UART
 	select DRIVERS_UART_8250MEM_32

src/soc/intel/skylake/bootblock/bootblock.c

@@ -28,7 +28,7 @@ void bootblock_soc_early_init(void)
 	bootblock_pch_early_init();
 	bootblock_cpu_init();
 
-	if (IS_ENABLED(CONFIG_BOOTBLOCK_CONSOLE))
+	if (IS_ENABLED(CONFIG_UART_DEBUG))
 		pch_uart_init();
 }