Some minor fixes for SPI flash on the Pinebook Pro and also default to saving environment to the SPI flash as it's guaranteed to be on board. Signed-off-by: Peter Robinson <pbrobinson@gmail.com> Reviewed-by: Kever Yang <kever.yang@rock-chips.com> (applied with make savedefconfig) Signed-off-by: Kever Yang <kever.yang@rock-chips.com>