drm/etnaviv: Remove redundant NULL check

Fix the following coccicheck warnings:

./drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c:622:2-8: WARNING: NULL
check before some freeing functions is not needed.

./drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c:618:2-8: WARNING: NULL
check before some freeing functions is not needed.

./drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c:616:2-8: WARNING: NULL
check before some freeing functions is not needed.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c

@@ -612,13 +612,9 @@ int etnaviv_ioctl_gem_submit(struct drm_device *dev, void *data,
 err_submit_cmds:
 	if (ret && (out_fence_fd >= 0))
 		put_unused_fd(out_fence_fd);
-	if (stream)
 	kvfree(stream);
-	if (bos)
 	kvfree(bos);
-	if (relocs)
 	kvfree(relocs);
-	if (pmrs)
 	kvfree(pmrs);
 
 	return ret;