[media] v4l: vsp1: dl: Fix race conditions

The vsp1_dl_list_put() function expects to be called with the display
list manager lock held. This assumption is correct for calls from within
the vsp1_dl.c file, but not for the external calls. Fix it by taking the
lock inside the function and providing an unlocked version for the
internal callers.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>