drm: atmel-hlcdc: actually disable scaling when no scaling is required

drm: atmel-hlcdc: actually disable scaling when no scaling is required

commit 1b7e38b92b0bbd363369f5160f13f4d26140972d upstream.

The driver is only enabling scaling, but never disabling it, thus, if you
enable the scaling feature once it stays enabled forever.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reported-by: Alex Vazquez <avazquez.dev@gmail.com>
Reviewed-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Fixes: 1a396789f65a ("drm: add Atmel HLCDC Display Controller support")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>