net: qed: cleanup global structs declarations

Fix several sparse warnings by moving structs declarations into
the corresponding header files:

drivers/net/ethernet/qlogic/qed/qed_dcbx.c:2402:32: warning:
symbol 'qed_dcbnl_ops_pass' was not declared. Should it be static?

drivers/net/ethernet/qlogic/qed/qed_ll2.c:2754:26: warning: symbol
'qed_ll2_ops_pass' was not declared. Should it be static?

drivers/net/ethernet/qlogic/qed/qed_ptp.c:449:30: warning: symbol
'qed_ptp_ops_pass' was not declared. Should it be static?

drivers/net/ethernet/qlogic/qed/qed_sriov.c:5265:29: warning:
symbol 'qed_iov_ops_pass' was not declared. Should it be static?

(some of them were declared twice in different header files)

Also make qed_hw_err_type_descr[] const while at it.

Signed-off-by: Alexander Lobakin <alobakin@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>