[PATCH] vesafb: Trim vesafb_pan_display

Remove error checking from vesafb_pan_display.  This is guaranteed to be done
by the core layer.

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>