scsi: be2iscsi: Fix POST check and reset sequence

SLIPORT FUNCTION_RESET does not reset the chip.
So POST status needs to be checked before issuing FUNCTION_RESET.
The completion of FUNCTION_RESET is indicated in BMBX Rdy bit.

be_cmd_fw_initialize too needs to be done before issuing any cmd to FW.
be_cmd_fw_initialize is renamed as beiscsi_cmd_special_wrb.
Rearrange and rename few functions in init and cleanup path.

Signed-off-by: Jitendra Bhivare <jitendra.bhivare@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>