SMM: Add option for SPI driver to be available in SMM

- add Kconfig option for CONFIG_SPI_FLASH_SMM
- compile subsystem and chip drivers for smm if enabled
- change mdelay(1) to udelay(500) since mdelay is not defined
  in SMM and a 1ms delay is worth avoiding
- make flash chip structure non-const so the probe function
  pointers can be relocated for use in TSEG
- Make SMM PCI access possible in southbridge SPI code

Change-Id: Icfcbbe8e4e56658769d46af0b5bf6c79a6432641
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/1313
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
diff --git a/src/southbridge/intel/bd82x6x/Makefile.inc b/src/southbridge/intel/bd82x6x/Makefile.inc
index 11a6b08..3de2bd0 100644
--- a/src/southbridge/intel/bd82x6x/Makefile.inc
+++ b/src/southbridge/intel/bd82x6x/Makefile.inc
@@ -33,6 +33,7 @@
 ramstage-y += watchdog.c
 
 ramstage-y += spi.c
+smm-$(CONFIG_SPI_FLASH_SMM) += spi.c
 
 ramstage-$(CONFIG_HAVE_SMI_HANDLER) += smi.c
 smm-$(CONFIG_HAVE_SMI_HANDLER) += smihandler.c me.c me_8.x.c finalize.c