msm: kgsl: Export device state to devfreq

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
msm: kgsl: Delay the first devfreq status read

No reason to read status when there hasn't been any activity
yet.  Wait at least one sample period after the GPU has been
turned on before pinging devfreq to read status.

Signed-off-by: Lucille Sylvester <lsylvest@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
PM / devfreq: Rewrite devfreq_update_status() to fix multiple bugs

The current devfreq_update_status() has the following bugs:
- When the new frequency doesn't have a valid level, the time spent in the
  new frequency is counted towards the next valid frequency switch instead
  of being ignored.
- The time spent on the previous frequency is added to the new frequency's
  stats instead of the previous frequency's stats.

This patch fixes all of this.

Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
PM / devfreq: Check for GPU busy time before sending the sample

Sometimes GPU busy time is very low during sampling. Accumulate
the statistics and send them with the next sample.

Signed-off-by: Suman Tatiraju <sumant@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>