msm_rmnet: merge support for RAWIP msm_rmnet device

Add to support for msm_rmnet device using ARPHRD_RAWIP.

CRs-Fixed: 1078373
Change-Id: Ie1e5433f440b26b644cccb18083ef325129f7942
Acked-by: Andrew Richardson <randrew@qualcomm.com>
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>