Define DEFAULT_WIN as zero to help set the primary plane on all CRTCs.
Some CRTCs were defining a variable to store the default window, but that
is not necessary as the default (primary) window is always the window zero.
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Inki Dae <inki.dae@samsung.com>