msm: memory_dump: move memory dump driver to drivers/soc/qcom

Architectural changes in the ARM Linux kernel tree mandate
the eventual removal of the mach-* directories. Move the
memory dump driver to drivers/soc/qcom and the memory dump header
to include/soc/qcom to support that removal.

Change-Id: If04f6a4fcd30c864321ac0ff8c6691fc20707cc1
Signed-off-by: Xiaogang Cui <xiaogang@codeaurora.org>
Signed-off-by: Aparna Das <adas@codeaurora.org>