msm: RMNET SDIO Data Mux module.

Module to allow RMNET over SDIO link. As multiple rmnet ports
need to use single SDIO line (function), muxing of the rmnet
packets is required.

Change-Id: I0b0cea7a2135ba4afdc00ce4faf6a28fda5dc929
Signed-off-by: Niranjana Vishwanathapura <nvishwan@codeaurora.org>