fpga: altera-cvp: Add Stratix10 (V2) Support

Add Stratix10 specific functions that use a credit mechanism
to throttle data to the CvP FIFOs. Add a private structure
with function pointers for V1 vs V2 functions.

Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>