[U-Boot] [U-Boot,v4,18/19] dfu: fix spl build

[Philipp Tomsich]

> In current state dfu depends on cmd/mtdparts.c which isn't build in SPL.
> This patch resolves it by cutting out unwanted code in SPL build.
> 
> Signed-off-by: Paweł Jarosz <paweljarosz3691 at gmail.com>
> ---
> Changes since v1:
> - none
> 
> Changes since v2:
> - none
> 
> Changes since v3:
> - removed unneded space
> 
>  drivers/dfu/dfu_nand.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 

Reviewed-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>