msm: Add idle_stats_device infrastructure

Add a core infrastructure for transmitting idle stats to user
space for use by other devices in the system such as the GPU.

Signed-off-by: Lucille Sylvester <lsylvest@codeaurora.org>
(cherry picked from commit 611d0d9e5b51f9e9906c956b619a91a35964210d)

Conflicts:

	arch/arm/mach-msm/Makefile

Change-Id: Ifed8a2636be0d381f616568ad85764d5e64a1757