MFC r257654
cxgbe(4): Exclude MPS_RPLC_MAP_CTL (0x11114) from the register dump.  Turns
out it's a write-only register with strange side effects on read.
MFC r257772, r258441, and r258689.

r257772:
cxgbe(4): Tidy up the display for payload memory statistics (pm_stats).

# sysctl -n dev.t4nex.0.misc.pm_stats
# sysctl -n dev.t5nex.0.misc.pm_stats

r258441:
cxgbe(4): update the internal list of device features.

r258689:
Disable an assertion that relies on some code[1] that isn't in HEAD yet.

[1] http://lists.freebsd.org/pipermail/freebsd-net/2013-August/036573.html