intel/apollolake: Calculate BIOS mmap at runtime

Instead of hard-coding the BIOS region start and end addresses, read
BIOS_BFPREG to determine the base and limit for the mapped BIOS
region.

BUG=chrome-os-partner:54563

Change-Id: Iddd3d4cc945f09e8f147e293bb9144471a6a220d
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/15269
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)

src/soc/intel/apollolake/Makefile.inc

@@ -56,11 +56,13 @@ ramstage-y += tsc_freq.c
 ramstage-y += pmutil.c
 ramstage-y += pmc.c
 ramstage-y += smi.c
+ramstage-y += spi.c
 ramstage-y += reset.c
 
 postcar-y += exit_car.S
 postcar-y += memmap.c
 postcar-y += mmap_boot.c
+postcar-y += spi.c
 postcar-$(CONFIG_SOC_UART_DEBUG) += uart_early.c
 postcar-y += tsc_freq.c
 
@@ -71,6 +73,7 @@ verstage-$(CONFIG_SOC_UART_DEBUG) += uart_early.c
 verstage-y += tsc_freq.c
 verstage-y += pmutil.c
 verstage-y += reset.c
+verstage-y += spi.c
 
 CPPFLAGS_common += -I$(src)/soc/intel/apollolake/include