uboot-imx

efi_loader: size of media device path node represenation

In the format specifier we want to specify the maximum width
in case an ending \0 is missing.

So slen must be used as precision and not as field width.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>