Separate out PCI attachment from the main AHCI driver. Move checks of
PCI IDs into quirks, which mostly fit (though you'd get no argument
from me that AHCI_Q_SATA1_UNIT0 is oddly specific). Set these quirks
in the PCI attachment. Make some shared functions public so that PCI
and possibly other bus attachments can use them.

The split isn't perfect yet, but it is functional. The split will be
perfected as other bus attachments for AHCI are written.

Sponsored by: Netflix
Reviewed by: kan, mav
Differential Revision: https://reviews.freebsd.org/D699
Remove an initialized, but otherwise, unused variable.
use a straight buffer instead of an iov w/ 1 segment...  The aesni
driver when it hits a mbuf/iov buffer, it mallocs and copies the data
for processing..  This improves perf by ~8-10% on my machine...

I have thoughts of fixing AES-NI so that it can better handle segmented
buffers, which should help improve IPSEC performance, but that is for
the future...
Apply known workarounds for modern MacBooks.

The legacy USB circuit tends to give trouble on MacBook.
While the original report covered MacBook, extend the fix
preemptively for the newer MacBookPro too.

PR:		191693
Reviewed by:	emaste
MFC after:	5 days
Bring in forgotten pinfunc.h files from last import.
Merge forgotten .h files from vendor branch.
Merge remote-tracking branch 'freebsd/master' into hardened/current/segvguard