From: Malcom Parsons <malcolm.parsons@gmail.com>

When scrolling up in SCROLL_PAN_REDRAW mode with a large limited scroll
region, the bottom few lines have to be redrawn.  Without this patch, the
wrong text is drawn into these lines, corrupting the display.

Observed in 2.6.14 when running an IRC client in the Nintendo DS linux
port.

I haven't tested if scrolling down has the same problem.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>