northbridge/intel/x4x: clean up includes

- Don't redefine D0F0_PCIEXBAR_LO, use the #define in x4x.h
- Move TPMBASE and TPM32() definitions into iomap.h
- Use "" style include for x4x.h in nortbridge files.
- Move includes of .h files out of x4x.h and into the c files that need
them.
- Protect function definitions in bootblock.

Change-Id: I3fdb579235c5446733a0ffba05fffe1a73381251
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/12849
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
6 files changed