soc: qcom: smd: Transition client drivers from smd to rpmsg

By moving these client drivers to use RPMSG instead of the direct SMD
API we can reuse them ontop of the newly added GLINK wire-protocol
support found in the 820 and 835 Qualcomm platforms.

As the new (RPMSG-based) and old SMD implementations are mutually
exclusive we have to change all client drivers in one commit, to make
sure we have a working system before and after this transition.

Acked-by: Andy Gross <andy.gross@linaro.org>
Acked-by: Kalle Valo <kvalo@codeaurora.org>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>