drm/amdkfd: Check for pdd drm file first in CRIU restore path

drm/amdkfd: Check for pdd drm file first in CRIU restore path

CRIU restore ioctls are meant to be called by CRIU with no
existing drm file. There's an error path
for if the drm file unexpectedly exists. It was positioned so
it was missing a fput(drm_file).

Do that check earlier, as soon as we have the pdd.

Signed-off-by: David Francis <David.Francis@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>