drm/amd/powerplay: fix amdgpu_pm_info show gpu load error

due to the smu dma/RTOS restriction, the interval of catching smu
metric table should be more than 1ms. otherwise it will cause the gpu
activity data corruption.

Signed-off-by: Kevin Wang <kevin1.wang@amd.com>
Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>