MLK-20208-1 mxc IPUv3: device: Remove a piece of dead code in ipu_task_thread()

MLK-20208-1 mxc IPUv3: device: Remove a piece of dead code in ipu_task_thread()

The check on !sp_tsk0 is unnecessary in ipu_task_thread(), because the
beforehand "list_del(&sp_tsk0->node);" within the context implies sp_tsk0
is not null, otherwise, we'll dereference a null pointer earlier.

Detected by CoverityScan, CID#17842 ("Logically dead code")

Signed-off-by: Liu Ying <victor.liu@nxp.com>
(cherry picked from commit 9ad5edd076d61bc8bb3a558e523cc7b31f2c3043)
Signed-off-by: Arulpandiyan Vadivel <arulpandiyan_vadivel@mentor.com>
Signed-off-by: Shrikant Bobade <Shrikant_Bobade@mentor.com>
(cherry picked from commit 2c4dd0cb989176b9ca71b7ee60e9cdb899f5f633)