staging: bcm2835-camera: Convert delayed_buffer to u32

A delayed buffer field is passed between the firmware and the
kernel.  This field is never used either so it's safe to
change it to a u32.

Signed-off-by: Michael Zoran <mzoran@crowfest.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>