CHROMIUM: cpufreq: interactive: validate above_hispeed_delay

We rely on the frequencies in above_hispeed_delay being in ascending
order.  Ensure that is the case for the values the user gives us.

BUG=chrome-os-partner:20830
TEST=Boot Pit; write invalid above_hispeed_delay value:
localhost ~ # echo "20000 1800000:20000 700000:0" > above_hispeed_delay
-bash: echo: write error: Invalid argument

Change-Id: Ifb431e58ad4b6b371152d7b09fcbefa127b0cbe2
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/65742


Reviewed-by: Sonny Rao <sonnyrao@chromium.org>

Used commit: https://github.com/jjhitel/ASKernel/commit/8d5ee9b7734594310b5f355cb869fa859de7a402