pxafb: preliminary smart panel interface support (update)

FB_PXA_SMARTPANEL defaults to "n" and removed the cast to void *.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Acked-by: Eric Miao <eric.miao@marvell.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
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>