ARM: dts: msm: setup child parent relationship for rmnet data

Setting up RSC child node so correct number of buffers can
be allocated.

CRs-Fixed: 2468499
Change-Id: Ibedc9deda155ab7be7fe30a227504ee1d93b3e0e
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>