Kconfig: Make stage cache kconfig selection proper

This patch makes stage cache kconfig proper

1. Define kconfig options as below for platform to select
(A) EXTERNAL_STAGE_CACHE
(B) CBMEM_STAGE_CACHE
(C) NO_STAGE_CACHE
- Selecting (A) or (B) will enable CONFIG_STAGE_CACHE
2. Modify .inc and .c as applicable with those configs.

Change-Id: I45e894ad335a4661cc7916b3768e1614a038b31c
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
---
M src/Kconfig
M src/arch/x86/Makefile.inc
M src/arch/x86/acpi_s3.c
M src/arch/x86/gdt.c
M src/arch/x86/memlayout.ld
M src/cpu/intel/haswell/Makefile.inc
M src/cpu/intel/model_2065x/Kconfig
M src/cpu/intel/model_206ax/Kconfig
M src/cpu/intel/model_206ax/Makefile.inc
M src/cpu/intel/smm/gen1/smmrelocate.c
M src/drivers/intel/fsp2_0/Makefile.inc
M src/include/stage_cache.h
M src/lib/Makefile.inc
M src/lib/prog_loaders.c
M src/northbridge/amd/amdfam10/Kconfig
M src/northbridge/intel/gm45/Kconfig
M src/northbridge/intel/gm45/Makefile.inc
M src/northbridge/intel/haswell/Kconfig
M src/northbridge/intel/i945/Kconfig
M src/northbridge/intel/i945/Makefile.inc
M src/northbridge/intel/pineview/Kconfig
M src/northbridge/intel/pineview/Makefile.inc
M src/northbridge/intel/x4x/Kconfig
M src/northbridge/intel/x4x/Makefile.inc
M src/northbridge/via/vx900/Kconfig
M src/soc/amd/stoneyridge/Kconfig
M src/soc/intel/apollolake/Kconfig
M src/soc/intel/braswell/Kconfig
M src/soc/intel/broadwell/Kconfig
M src/soc/intel/cannonlake/Kconfig
M src/soc/intel/fsp_baytrail/Kconfig
M src/soc/intel/icelake/Kconfig
M src/soc/intel/skylake/Kconfig
33 files changed, 88 insertions(+), 72 deletions(-)