soc/intel/apollolake: Add cbmem_top() implementation

On Apollolake CPU memory mapping is similar to previous SoC, and
we place CBMEM right under TSEG.

Change-Id: I606f690449ba98af6e9fc3074d677c7287892164
Signed-off-by: Andrey Petrov <andrey.petrov@intel.com>
Reviewed-on: https://review.coreboot.org/13883
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/intel/apollolake/Makefile.inc

@@ -20,12 +20,14 @@ romstage-y += placeholders.c
 romstage-$(CONFIG_PLATFORM_USES_FSP2_0) += romstage.c
 romstage-y += gpio.c
 romstage-$(CONFIG_SOC_UART_DEBUG) += uart_early.c
+romstage-y += memmap.c
 romstage-y += mmap_boot.c
 
 smm-y += placeholders.c
 ramstage-y += placeholders.c
 ramstage-y += gpio.c
 ramstage-$(CONFIG_SOC_UART_DEBUG) += uart_early.c
+ramstage-y += memmap.c
 ramstage-y += mmap_boot.c
 
 CPPFLAGS_common += -I$(src)/soc/intel/apollolake/include