[coreboot] [PATCH]Implement per chipset rom enable sequence framework, and enable Fam10 build with Kconfig

[Patrick Georgi]

Hi,

attached patch implements a framework to do rom enable sequences for the
tinybootblock system and implements the rom enable for Fam10.

Changes:
- Pass BIST through the bootblock (AMD wants this)
- Rework walkcbfs to leave two registers unused, so BIST doesn't break
romcc on non-mmx/sse systems
- Provide enable_rom code for Fam10 northbridge and AMD8111 southbridge
and hook it up in amd/serengeti_cheetah_fam10

Build tested on amd/serengeti_cheetah_fam10 and emulation/qemu-x86. QEmu
is also boot-tested, the AMD board failed in my last tests. As I'm out
of ideas on what might be wrong in Fam10 init, I decided to publish it -
it's an improvement over what we have now, right? ;-)

Signed-off-by: Patrick Georgi

Regards,
Patrick