Use timer.h helpers instead of open-coding timeout handling in polling
loops. The 25-microsecond delay in `wait_for_valid` looks odd, and may
be removed in subsequent commits. For now, preserve existing behavior.
Change-Id: Id1227c6812618597c37408a7bf53bcbcae97374a
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50789
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
9f5261e5fa