Change in coreboot[master]: soc/amd/common/block/cpu: Cache the uCode to avoid multiple SPI reads

[Raul Rangel (Code Review)]

Attention is currently required from: Jason Glenesk, Furquan Shaikh, Martin Roth, Marshall Dawson, Felix Held.
Raul Rangel has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/55987 )

Change subject: soc/amd/common/block/cpu: Cache the uCode to avoid multiple SPI reads
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Patch Set 4:

(1 comment)

File src/soc/amd/common/block/cpu/update_microcode.c:

https://review.coreboot.org/c/coreboot/+/55987/comment/41bf2a42_4dd56fbf 
PS3, Line 112: ucode_list
> Since the parent CL was abandoned, this needs to be reworked.

Dropped the const.