msm: kgsl: Write the retired timestamp on resume

Write the retired timestamp into the expected location. This fixes
userspace crashes after resume when the retired timestamp is read
as 0 instead of the expected last timestamp.

CRs-Fixed: 350556
Change-Id: Iaa487ba8be427c29b9f7e9b30b251cf26fcff95a
Signed-off-by: Lynus Vaz <lvaz@codeaurora.org>