mali_kbase: metrics: Disable metrics timer on suspend

This change ensures that the hr_timer that calculates GPU
metrics and informs the DVFS routines in the platform
integration are disabled when the system goes into suspend
and wakes them up on resume.

Bug: 169841520
Bug: 169802307
Signed-off-by: Sidath Senanayake <sidaths@google.com>
Change-Id: Ie4beb8d85adb53689fae6f92de3684f58c97ec71