msm: cache_dump: Support multiplatform

Convert to support multiplatform kernels.
This requires drivers to belocated in generic
functionality directories instead of specific
mach directories.

Move over the cache dump driver and related header
file to drivers/soc/qcom/ from arch/arm/mach-msm/

Change-Id: I82eeffda0ce811a1f0ddcfec2be9bd90ec575600
Signed-off-by: Abhimanyu Kapur <abhimany@codeaurora.org>