net: dpaa: Fix uninitialized variable in dpaa_stop()

The return value is not initialized on the success path.

Fixes: 901bdff2 ("net: fman: Change return type of disable to void")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: Madalin Bucur <madalin.bucur@oss.nxp.com>
Reviewed-by: Sean Anderson <sean.anderson@seco.com>
Link: https://lore.kernel.org/r/8c9dc377-8495-495f-a4e5-4d2d0ee12f0c@kili.mountain


Signed-off-by: Jakub Kicinski <kuba@kernel.org>