[S] Change in coreboot[master]: soc/intel/common: Make ramtop offset configurable

[Nico Huber (Code Review)]

Attention is currently required from: Sean Rhodes, Subrata Banik, Lean Sheng Tan.

Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/74511 )

Change subject: soc/intel/common: Make ramtop offset configurable
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Patch Set 3:

(1 comment)

File src/soc/intel/common/basecode/ramtop/ramtop.c:

https://review.coreboot.org/c/coreboot/+/74511/comment/197cecb6_1bd9ecb8 
PS2, Line 23: CMOS_VSTART_ramtop_cmos_offset
If there is no other code to sync with, I think we can just use
CMOS_VSTART_ramtop_cmos_offset w/o comparing it to anything redundant,
and fall back to the default value if no option table is used.

Something like

#if CONFIG(USE_OPTION_TABLE)
    #include "option_table.h"
    #if CMOS_VSTART_ramtop_cmos_offset % 8 == 0
    #define RAMTOP_CMOS_OFFSET (CMOS_VSTART_ramtop_cmos_offset / 8)
    #else
    #error ...
    #endif
    ...
    #else
    #define RAMTOP_CMOS_OFFSET 100
    #endif