of: del redundant type conversion

The type of variable l in early_init_dt_scan_chosen is
int, there is no need to convert to int.

Signed-off-by: xiaojiangfeng <xiaojiangfeng@huawei.com>
Reviewed-by: Frank Rowand <frank.rowand@sony.com>
Signed-off-by: Rob Herring <robh@kernel.org>