soc: qcom: mdt-loader: Return relocation base

In order to implement support for grabbing core dumps in remoteproc it's
necessary to know the relocated base of the image, as the offsets from
the virtual memory base might not be based on the physical address.

Return the adjusted physical base address to the caller.

Acked-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>