net: lantiq_etop: remove multiple assignments

Documentation/process/coding-style.rst says (in line 88)
"Don't put multiple assignments on a single line either."

This patch fixes the coding style issue reported by checkpatch.pl.

Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>