[LinuxBIOS] cache as ram for x86

[yhlu]

Ron,

It turns out that Cache as Ram can work in intel xeon too. The only
difference is AMD need to set some bits in SYSCFG_MSR.

So final cache as ram support for x86 will be
cpu/x86/car/cache_as_ram.inc
cpu/x86/car/cache_as_ram_post.c
cpu/x86/car/copy_and_run.c

there is special version for AMD
cpu/amd/car/cache_as_ram.inc
cpu/amd/car/cache_as_ram_post.c

in MB dir 
cache_as_ram_auto.c it will include old failover.c and auto.c and
corresponding cache_as_ram_post.c and copy_and_run.c

the cache_as_ram_post.c will stop the cache as ram and switch to ram stack.
copy_and_run will decode linuxbios_ram to memory, and jmp to it.

USE_DCACHE_RAM  ---> use romcc or gcc for auto.c...
CONFIG_USE_INIT ----> use init or not.

the code can coexist with romcc .....

If it is ok, I will check in cache as ram support for s2735 and
s2885/s2891/s2895 tomorrow.

Also I would help to verify that on other x86 platform.

YH