msm: kgsl: Don't update devfreq if the device is in slumber [Suman Tatiraju]

There is no need to notify devfreq with the device statistics
if the device is power collapsed.

Change-Id: I57af414fa66417226dcb682ac3fcb088503fa5ab
Signed-off-by: Suman Tatiraju <sumant@codeaurora.org>