remoteproc: Move qcom_mdt_loader into drivers/soc/qcom

With the remoteproc parts cleaned out of the MDT loader we can move it
to drivers/soc/qcom.

Acked-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
(cherry picked from commit 2aad40d9)