drm/amdkfd: fix clock counter retrieval for node without GPU

drm/amdkfd: fix clock counter retrieval for node without GPU

[ Upstream commit 1cf6cc74bbeb85bb87c3ca3f3df97a283c3aa737 ]

Currently if a user requests clock counters for a node without a GPU
resource we will always return EINVAL.

Instead if no GPU resource is attached, fill the gpu_clock_counter
argument with zeroes so that we may proceed and return valid CPU
counters.

Signed-off-by: Andres Rodriguez <andres.rodriguez@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>