Change in coreboot[master]: util/apcb/apcb_v3_edit.py: Edit APCB based on different SPD magic

[Raul Rangel (Code Review)]

Attention is currently required from: Rob Barnes, Karthik Ramasubramanian.
Raul Rangel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/63598 )

Change subject: util/apcb/apcb_v3_edit.py: Edit APCB based on different SPD magic
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Patch Set 1:

(2 comments)

File util/apcb/apcb_v3_edit.py:

https://review.coreboot.org/c/coreboot/+/63598/comment/345973a5_89836d58 
PS1, Line 84: if args.spd_magic:
            :         SPD_MAGIC = bytes.fromhex(args.spd_magic)
Can you use a local variable instead?

```
if args.spd_magic:
        spd_magic = bytes.fromhex(args.spd_magic)
else:
        spd_magic = SPD_MAGIC
```

https://review.coreboot.org/c/coreboot/+/63598/comment/1818aca5_df3d6f5f 
PS1, Line 97: SPD_MAGIC
Switch this to use `spd_magic`