Since we now use the generic backlight infrastructure, I think we need to
call rivafb_bl_init before calling register_framebuffer since otherwise
rivafb_bl_init might race with the framebuffer layer already opening the
device and setting up the video mode.  In this case we might end up with a
not yet fully intialized backlight (info->bl_dev still NULL) when calling
riva_bl_set_power via rivafb_set_par/rivafb_load_video_mode and the kernel
dies without any further notice during boot.

This fixes booting current git on a PB 6,1.  In this case radeonfb/atyfb
would be affected too - I can fix that too but don't have any hardware to
test this on.

Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>