qed: fix old-style function definition

The newly added file causes a harmless warning, with "make W=1":

drivers/net/ethernet/qlogic/qed/qed_iscsi.c: In function 'qed_get_iscsi_ops':
drivers/net/ethernet/qlogic/qed/qed_iscsi.c:1268:29: warning: old-style function definition [-Wold-style-definition]

This makes it a proper prototype.

Fixes: fc831825

 ("qed: Add support for hardware offloaded iSCSI.")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>