Fix a regression introduced by SVN r257842; resulting in mountroot prompt
after attempting to install to encrypted ZFS root (caused by a typo in a
variable name -- ZFSBOOT_BOOT_FSNAME -> ZFSBOOT_BOOTFS_NAME).

MFC after:	3 days
Print out the full PCIe link negotiation during dmesg.

I found this useful when checking whether a NIC is in a PCIE 3.0 8x slot
or not.

Reviewed by:	np
Sponsored by:	Netflix, inc.