drm/amdgpu: skip the invalid workload type

If some invalid workload types exposed by the power profile sysfs node,
it will be failed to set the unsuported profiles.
So we can skip to show the invalid workload type in the profiles list to
avoid that failure happen.

Acked-by: Kenneth Feng <kenneth.feng@amd.com>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>