Remove the use of bit field in structure.

[cathay4t]

Using bit field in structure is hard to maintain and might be an issue for big endian system.

I created some function for bit filed manipulation for nvme kernel.
Maybe we create something similar for our SCSI bit fileds.
The difference between NVMe and SCSI standard on using bit filed:

• SCSI standard are using bytes numebr + bit number.
• NVMe standard are using total bit range.