Revert "CHROMIUM: cpufreq: interactive: run at fraction of hispeed_freq when load is low"

- should have reviewed history prior to commiting. heh
This reverts commit 01725e884f7cc33b86fed5441e85936ee44ca90c.
Makefile: re-include -mtune flag for Cortex-A9

After running only -mcpu for some time and a bit of testing, including
this bunch (-mtune, -march, -mcpu) has yielded an overall increase in
benchmarking scores (0xBenchmark). The differences aren't staggering or
anything, but people like nicer benchmarks.

Signed-off-by: Luis Cruz <ljc2491@gmail.com>