msm: kgsl: Do not always wait for 200ms in regulator disable check

We check for regulator to be disabled after we disable the GPU regulator.
During this check we are incorrectly waiting for 200ms always. Once
regulator is detected to be disabled exit the wait loop

Change-Id: I52393bdd2b535a495f4f61d475a9d9ede0fb8b9b
Signed-off-by: Tarun Karra <tkarra@codeaurora.org>
Signed-off-by: Oleg Perelet <operelet@codeaurora.org>