drm/sched: move calling drm_sched_entity_select_rq

We already discussed that the call to drm_sched_entity_select_rq() needs
to move to drm_sched_job_arm() to be able to set a new scheduler list
between _init() and _arm(). This was just not applied for some reason.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220714103902.7084-2-christian.koenig@amd.com