s3c-fb: fix off-by-one bug in loop indexes

Fixed off-by-one bug in loop indexes - some elements beyond windows' array
were accessed, which might result in memory access violations when
removing/suspending the device.

Signed-off-by: Pawel Osciak <p.osciak@samsung.com>
Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>