drm/amd/display: Avoid get/put vblank when stream disabled

[Why]
amdgpu_dm_crtc_set_crc_source() will call
amdgpu_dm_crtc_configure_crc_source() to enable/disable CRC
generation. However, configuration will be deferred to stream enabled.
If stream is not enabled, current flow will still try to get/put vblank
refcount.

[How]
Return EINVAL to skip actions on vblank refcount when stream is not
enabled.

Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
Reviewed-by: Chao-kai Wang <Stylon.Wang@amd.com>
Acked-by: Stylon Wang <stylon.wang@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>