Restore "u-boot: Relax KCFLAGS warnings for GCC 15" This reverts commit d0b41d26f87389b1c8dded21777e20739130aa1f. Reason for revert: unbreak the build. See also https://fusion2.corp.google.com/invocations/67c2e49b-452f-4b82-ae43-6be41ccb8728/targets/gbmc%2Ffirmware-build%2Fpresubmit/log Tested: this is a revert Google-Bug-Id: 558753346 Change-Id: I4223ece3b5ddfeca7d4f31068f280f96e1da255d Signed-off-by: Bart Van Assche <bvanassche@google.com>