Intel FSP: add a shared set of functions for the FSP

- Move the non chipset-specific fsp pieces out of the chipset into a
shared area.  This is used by northbridge / southbrige / SOC code.  It
pulls in pieces from Kconfig, Makefile and FSP specific code.
- Enabled in the CPU code with a Kconfig "select PLATFORM_USES_FSP"

Change-Id: I7ffa934c1df09b71d48a876a56e3b888685870b8
Signed-off-by: Martin Roth <gaumless@gmail.com>
Signed-off-by: Martin Roth <martin.roth@se-eng.com>
Reviewed-on: http://review.coreboot.org/5635
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

src/Kconfig

@@ -256,6 +256,7 @@ comment "Embedded Controllers"
 source src/ec/Kconfig
 comment "SoC"
 source src/soc/Kconfig
+source src/drivers/intel/fsp/Kconfig
 
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