s3c-fb: correct window osd size and alpha register handling

s3c-fb: correct window osd size and alpha register handling

S3C64xx and S5P OSD registers for OSD size and alpha are as follows:
VIDOSDC: win 0 - size, win 1-4: alpha
VIDOSDD: win 1-2 - size; not present for windows 0, 3 and 4

Signed-off-by: Pawel Osciak <p.osciak@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: InKi Dae <inki.dae@samsung.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>