msm: kgsl: Idle the core before changing the gpu clock.

Idle the core before changing the gpu clock as instability
is caused on some platforms on changing the clock freq when
core is busy.

CRs-fixed: 328249
Change-Id: I5f6a507eaad383bde646001d2e10c2b62880515b
Signed-off-by: Kedar Joshi <kjoshi@codeaurora.org>
4 files changed