seandroid: Restructuring sepolicy codebase

Seandroid codebase is restructured using this gerrit
All the sepolicies which are common acress all the
chipsets needs to be kept inside common folder. And
all the other policies which are specific to target,
should be kept inside the folder with the chipset name
i.e, all the policies specific to 8084 should be
inside apq8084 folder.

Change-Id: I14734e2d3b9d6a0846a2c99e942c8da9495fa6ab