[Bugfix][API-1269]fix ethernet memory leak

Only Configure: No
Affected branch: GSW3.0-no-connman
Affected module: ethernet
Is it affected on both ZXIC and MTK: only MTK
Self-test: No
Doc Update: No

Change-Id: Id9ed2413ca852f2414f65a84daf8ce16134d5fa9
(cherry picked from commit 02517cbb318c5bc2b3535e025f205d955423d7a7)
6 files changed