soc/intel/{broad,cannon,sky}: Fix possible out-of-bounds reads

soc/intel/{broad,cannon,sky}: Fix possible out-of-bounds reads

There will be a possible out of bounds array access if
power_limit_1_time == ARRAY_SIZE(power_limit_time_sec_to_msr), so
prevent that in the index check. This issue was fixed for other cpus in
commit 5cfef13f8d (cpu/intel: Fix out-of-bounds read due to off-by-one
in condition). Based on the discussion for that commit, also remove the
magic constant 28 in favour of the index of the last array element.

Change-Id: Ic3f8735b23a368f8a9395757bd52c2c40088afa1
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Found-by: Coverity CID 1229673
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34498
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>