MFC r237832, r237436, r237439, r237463, r237512, r237587, r237799,

MFC r237832, r237436, r237439, r237463, r237512, r237587, r237799,
r237819, r237831.

r237832:
cxgb(4): IPv6 rx/tx hw checksum, IPv6 TSO and LRO too.

r237436:
cxgbe(4): update to firmware interface 1.5.2.0; updates to shared code.

r237439:
Do not read registers with read side effects while performing a register
dump for cxgbetool.

r237463:
Do not allocate extra vectors when adapter is not TOE
capable (or toecaps have been disallowed by the user).

r237512:
Better way to determine the status page length and rx pad boundary.

r237587:
Allow cxgbe(4) running within a VM to attach to its devices that have been
exported via PCI passthrough.

r237799:
cxgbe(4): support for IPv6 hardware checksumming (rx and tx).

r237819:
cxgbe(4): support for IPv6 TSO and LRO.

r237831:
- Assign (don't OR) the CSUM_XXX bits to csum_flags in the rx checksum code.
- Fix TSO/TSO4 mixup.
- Add IFCAP_LINKSTATE to the available/enabled capabilities.

git-svn-id: svn://svn.freebsd.org/base/stable/9@237925 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f