msm: smem: Support multiplatform

Upstream prefers existing drivers be converted to support multiplatform
kernels.  This requires drivers to be located in generic functionality
directories instead of specific mach directories.

Move the smem driver to the drivers/soc/msm location to support
multiplatform.

Change-Id: I9ba6eedce5237be6b96850e772232182a1a084ae
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>