qed: move chain methods to a separate file

Move chain allocation/freeing functions to a new file to not mix it with
hardware-related code.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alexander Lobakin <alobakin@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: Michal Kalderon <michal.kalderon@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>