MFC r222897:

MFC r222897:
Intel NM10 chipset's SATA controller has same PCI ID and revision as ICH7's,
but has only 2 SATA ports instead of 4. The worst part is that SStatus and
SError registers for missing ports are not implemented and return wrong
values (0xffffffff), that caused infinite reset loop.

Just ignore that SError value while I found no better way to identify them.

git-svn-id: svn://svn.freebsd.org/base/stable/8@223360 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f