AGESA SPI: Fix Kconfig options

Option AMD_SB_SPI_LEN leaked to non-AMD configs.
Option SPI_FLASH is compulsory with HAVE_ACPI_RESUME.

Change-Id: Ib84c4d9e4fdf670b32b0cae7280fcbb6d3aecaf5
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/5606
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Idwer Vollering <vidwer@gmail.com>

src/cpu/amd/agesa/Kconfig

@@ -29,6 +29,7 @@ config CPU_AMD_AGESA
 	select TSC_SYNC_LFENCE
 	select UDELAY_LAPIC
 	select LAPIC_MONOTONIC_TIMER
+	select SPI_FLASH if HAVE_ACPI_RESUME
 
 if CPU_AMD_AGESA