sched: sched_avg: Add snapshot of sched_avg

This snapshot is taken from msm-4.9 as of commit 12a64233c6b30a7
("sched: Fix for 32bit '__udivdi3' build error").

Change-Id: I2bac563ddd0985f0bc85a8d7fc6f3c9694c84264
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
[satyap@codeaurora.org:
 1. Resolve merge conflicts
 2. Fix compilation issues for ARCH=um
 3. Comment out parts of code for compilation]
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>