dm: core: Drop a few early returns

Two functions in this file return early for no good reason. Adjust the
code to match the standard DM style of returning 0 at the end of the
function on success.

Oddly enough this save 12 bytes of code size on ARM.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
1 file changed