MFC 296018,296640,296641,296689,296735,296949: Fixes for sysctl handlers.

296018:
cxgbe(4): Add a sysctl to retrieve the maximum speed/bandwidth supported by a
port.

dev.cxgbe.<n>.max_speed
dev.cxl.<n>.max_speed

296640:
cxgbe(4): Add a sysctl for the event capture mask of the TP block's
logic analyzer.

dev.t5nex.<n>.misc.tp_la_mask
dev.t4nex.<n>.misc.tp_la_mask

296641:
cxgbe(4): Add sysctls to display the TP microcode version and the
expansion rom version (if there's one).

trantor:~# sysctl dev.t4nex dev.t5nex | grep _version
dev.t4nex.0.firmware_version: 1.15.28.0
dev.t4nex.0.tp_version: 0.1.9.4
dev.t5nex.0.firmware_version: 1.15.28.0
dev.t5nex.0.exprom_version: 1.0.0.68
dev.t5nex.0.tp_version: 0.1.4.9

296689:
cxgbe(4): sysctls to display the TOE's TCP timers.

cask:~# sysctl -d dev.t5nex.0.toe
dev.t5nex.0.toe.finwait2_timer: FINWAIT2 timer (us)
dev.t5nex.0.toe.initial_srtt: Initial SRTT (us)
dev.t5nex.0.toe.keepalive_intvl: Keepidle interval (us)
dev.t5nex.0.toe.keepalive_idle: Keepidle idle timer (us)
dev.t5nex.0.toe.persist_max: Persist timer max (us)
dev.t5nex.0.toe.persist_min: Persist timer min (us)
dev.t5nex.0.toe.rexmt_max: Retransmit max (us)
dev.t5nex.0.toe.rexmt_min: Retransmit min (us)
dev.t5nex.0.toe.dack_timer: DACK timer (us)
dev.t5nex.0.toe.dack_tick: DACK tick (us)
dev.t5nex.0.toe.timestamp_tick: TCP timestamp tick (us)
dev.t5nex.0.toe.timer_tick: TP timer tick (us)
...

cask:~# sysctl dev.t5nex.0.toe
dev.t5nex.0.toe.finwait2_timer: 9765440
dev.t5nex.0.toe.initial_srtt: 244128
dev.t5nex.0.toe.keepalive_intvl: 73240800
dev.t5nex.0.toe.keepalive_idle: 7031116800
dev.t5nex.0.toe.persist_max: 9765440
dev.t5nex.0.toe.persist_min: 976544
dev.t5nex.0.toe.rexmt_max: 9765440
dev.t5nex.0.toe.rexmt_min: 244128
dev.t5nex.0.toe.dack_timer: 19520
dev.t5nex.0.toe.dack_tick: 32.768
dev.t5nex.0.toe.timestamp_tick: 1048.576
dev.t5nex.0.toe.timer_tick: 32.768
...

296735:
Fix the following gcc warnings on sparc64, when TCP_OFFLOAD is not
defined:

sys/dev/cxgbe/t4_main.c:7474: warning: 'sysctl_tp_tick' defined but not used
sys/dev/cxgbe/t4_main.c:7505: warning: 'sysctl_tp_dack_timer' defined but not used
sys/dev/cxgbe/t4_main.c:7519: warning: 'sysctl_tp_timer' defined but not used

This just adds a bunch of #ifdef TCP_OFFLOAD in the right places.

296949:
cxgbe(4): Remove a couple of pointless assignments in sysctl_meminfo.
Do not display range if start = stop (this is a workaround for some
unused regions).

Sponsored by: Chelsio Communications