[media] media: venus: hfi: add Venus HFI files

Here is the implementation of Venus video accelerator low-level
functionality. It contanins code which setup the registers and
startup uthe processor, allocate and manipulates with the shared
memory used for sending commands and receiving messages.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>