w100fb bugfix: The blanking function used vmalloc/vfree which isn't interrupt
safe.  To avoid problems, switch to kmalloc/kfree and use several buffers to
avoid kmalloc size limitations.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>