drm/scheduler: avoid redundant shifting of the entity v2

do not remove entity from the rq if the current rq is from
the least loaded scheduler.

Signed-off-by: Nayan Deshmukh <nayan26deshmukh@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>