gpu: Minimum sampling period

Set default sampling period to 1 ms, but support a minimum sampling
period of 0.5 ms.

Signed-off-by: Antonio Caggiano <antonio.caggiano@collabora.com>
Reviewed-by: Rohan Garg <rohan.garg@collabora.com>
3 jobs for min-sampling-period in 2 minutes and 38 seconds
Status Job ID Name Coverage
  Check
passed #6493355
clang-format

00:00:08

 
  Build
passed #6493357
aarch64
aarch64

00:02:29

passed #6493356
kvm
x86_64

00:01:23