msm: kgsl: Move kgsl_idle_check to target specific probe

We will be re-purposing the idle check structures to run different
idle check functions for gmu and rgmu based targets. So move the
relevant bits to target specific probe.

Change-Id: I27b936eb46568f3e5511257d67dd93c23407fd18
Signed-off-by: Harshdeep Dhatt <hdhatt@codeaurora.org>