soc/intel/apollolake: group serial console options into one Kconfig

Add SOC_UART_DEBUG which does all the appropriate selection of the
dependent Kconfig options for seral console. Also provide a default
option of it being turned off instead of always selected.

Change-Id: I1a6dba9c0072a17859c8f389709afe6fe3b04fac
Signed-off-by: Aaron Durbin <adurbin@chormium.org>
Reviewed-on: https://review.coreboot.org/13790
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Andrey Petrov <andrey.petrov@intel.com>

src/soc/intel/apollolake/Makefile.inc

@@ -13,16 +13,16 @@ bootblock-y += bootblock/bootblock.c
 bootblock-y += gpio.c
 bootblock-y += placeholders.c
 bootblock-y += tsc_freq.c
-bootblock-y += uart_early.c
+bootblock-$(CONFIG_SOC_UART_DEBUG) += uart_early.c
 
 romstage-y += placeholders.c
 romstage-y += gpio.c
-romstage-y += uart_early.c
+romstage-$(CONFIG_SOC_UART_DEBUG) += uart_early.c
 
 smm-y += placeholders.c
 ramstage-y += placeholders.c
 ramstage-y += gpio.c
-ramstage-y += uart_early.c
+ramstage-$(CONFIG_SOC_UART_DEBUG) += uart_early.c
 
 CPPFLAGS_common += -I$(src)/soc/intel/apollolake/include