This CL Move the V4L2 device and V4L2 device poller files to the common
code folder. In a next step these files will be cleaned up and reworked
into proper Android code, but splitting the move into a separate CL
makes the review process a lot easier.

Bug: 155138142
Test: arc.VideoEncodeAccel.h264_192p_i420_vm
Change-Id: I4c4c9d7f5c7e85feed10ed1e3fd9b8fa14ca67ae