ahci over time has grown a number of board IDs and it's a bit of mess
right now. Clean it up such that,
* board_id_* now live in a separate enum board_ids and numbers are
assigned automatically.
* Board IDs assigned to features are separated from the ones assigned
to specific implementations and both are ordered alphabetically.
* For NV MCPs, define per-generation alias board_ids and assign
matching aliases in the pci id table. This makes mcp_linux, 67-73
use board_ahci_mcp65 instead of board_ahci_yesncq. Both are
identical in content.
* Kill now unused board_ahci_nopmp and board_ahci_yesncq.
This patch doesn't cause any functional change but will make future
changes to board_ids and quirks much less painful.