Remove the need for callers to reference PROT_READ/PROT_WRITE directly
from <sys/mman.h> by instead exposing the Read/Write mapping options as
flags from the MappedFrameBuffer class itself.
While here, introduce the <stdint.h> header which is required for the
uint8_t as part of the Plane.
Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>