msm: kgsl: Activate the dispatcher following a resume

The dispatcher is put into pause during suspend to avoid commands coming in
during suspend.  Unfortunately the dispatcher never has a chance to unpause
itself on resume so new commands sit there waiting for the GPU to turn on.

Change-Id: Ic0dedbad6c9744b47fa1ae711d1b04735fa2f083
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>