[M] Change in coreboot[main]: arch/riscv: Factor out common romstage code

[Felix Held (Code Review)]

Attention is currently required from: Arthur Heymans, Maximilian Brune, Philipp Hug, Ron Minnich.

Felix Held has posted comments on this change by Maximilian Brune. ( https://review.coreboot.org/c/coreboot/+/83098?usp=email )

Change subject: arch/riscv: Factor out common romstage code
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Patch Set 5:

(1 comment)

File src/mainboard/sifive/hifive-unmatched/romstage.c:

https://review.coreboot.org/c/coreboot/+/83098/comment/d288444c_37f572d6?usp... :
PS5, Line 19: 	console_init();
> UART subsystem depends on `clock_init()`. […]

doing that in a separate patch sounds good to me, since it's a separate logical change. i'd prefer to have that patch before this one though