octeontx2-af: Add FLR handling support for AF's VFs

Added support to handle FLR for AF's VFs (i.e LBK VFs).
Just the FLR interrupt enable/disable, handler registration
etc, actual HW resource cleanup or LFs teardown logic is
already there.

Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>