[qca-nss-clients] Make qdisc module take a reference on IGS module.

The code change causes nss qdisc module to take a reference on the IGS
module when a qdisc is configured on an IFB interface. This ensure the
IGS module will not go away when shapers are configured on it.

Change-Id: Ib7748af0b0f41fb52afc77badc988626c4b8ec5a
Signed-off-by: Manish Verma <maniverm@codeaurora.org>
3 files changed