Revert "net: core: fix for ipv6 neigh"

This reverts commit bead6469.

Double timer is getting attached in some scenarios.
Unable to delete bridge as timer is not deleted.

Change-Id: I3b830f9666b93c39c64f7b16fe13f1fc79d17abd
Acked-by: Suraj Jaiswal <c_surajj@qti.qualcomm.com>
Signed-off-by: Mohammed Javid <mjavid@codeaurora.org>