drm/v3d: Use drm_sched_job_add_syncobj_dependency()

As v3d_job_add_deps() performs the same steps as
drm_sched_job_add_syncobj_dependency(), replace the open-coded
implementation in v3d in order to simply use the DRM function.

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20230209124447.467867-6-mcanal@igalia.com