cam nvme: Move opcode and status code tables from CTL to base CAM

This adds support for decoding admin opcodes to the existing opcode
decoding and also removes one of the duplicate NVMe opcode string
tables.

• Add nvme_opcode_sbuf and nvme_cpl_sbuf which are CCB type-independent and handle the guts of the CTL-specific routines.

• Use nvme_opcode_sbuf to decode the opcode in nvme_command_sbuf.

• Add nvme_status_sbuf to decode the CPL/CQE in a ccb_nvmeio.

Reviewed by: imp
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D50631