devfs: Improve devfs_alias_getvp()

* Resolve indirect alias nodes up to a relatively large limit

* Code taken from devfs_vop_nresolve()

Suggested-by: alexh
drm/i915: Make struct intel_gtt more compatible with Linux 3.8.13
drm/i915: use i915_ggtt_clear_range()
kernel: Import the IPMI driver from FreeBSD.

Many thanks to Markus Pfeiffer <profmakx@dragonflybsd.org> for testing,
bug hunting and fixing the watchdog (this will be pushed in a separate
commit).
sys/dev/misc/ipmi: Implement watchdog functionality

Unfortunately wdog(9) cannot handle how ipmi's watchdog works, so
we roll our own callout based solution.
Update the pciconf(8) database.

December 14, 2014 snapshot from http://pciids.sourceforge.net/
twa(4): Fix a crash with TWA_DEBUG >= 3.

tw_osli_dbg_dprintf() uses device_printf(sc->bus_dev, ...) so we can't
use it before sc->bus_dev is actually set.
drm/i915: Reduce GEM code differences with Linux 3.8.13
route/inet: Set the mtu if it is _not_ configured, i.e. is 0
icmp: Asynchonize ctlinput/mtudisc/redirect processing

Supportive facilities added:
- Embed netmsg_ctlinput into mbuf (used by input ICMP datagram) so that
  we don't need to do additional memory allocation to forward the
  pr_ctlinput to all netisrs for certain types of ICMP datagrams.
- Add/Expose so_pr_ctlport().
- Return target netisr's cpuid from pr_ctlport.  If the returned cpuid
  equals to ncpus, it means that pr_ctlinput needs to be run in all
  netisrs.
- Support 'direct' mode for TCP/UDP's pr_ctlinput.  The caller of the
  'direct' mode pr_ctlinput will do the message forwarding.

ICMP pr_ctlinput/mtudisc/redirect processing changes:
- For mtudisc and redirect we unconditionally forward the message
  embedded in input ICMP datagram to all netisrs, and call pr_ctlinput
  in 'direct' mode.
- For pr_ctlinput, we first call so_pr_ctlport() to see whether we need
  to forward the message embedded in input ICMP datagram to all netisrs,
  and act accordingly.
- Once pr_ctlinput/mtudisc/redirect processing is done, the message
  embedded in the input ICMP datagram is forwarded back to the netisr0
  to run rip_input().

After this commit, netisr0 will not be blocked for ICMP pr_ctlinput/
mtudisc/redirect processing.  This also fixes the mtudisc (originally
only cpu0's routes get mtu updates).
libc - Initialise ret before use
kernel/acpica: Separate kernel and userland code in headers better.

Clean up a bit, use standard types, etc.
libc/db - Fix a resource leak

- Detected by cppcheck
libc/regex - Fix a memory leak

- Detected by cppcheck
svc - Fix a couple memory leaks

- Detected by cppcheck
savecore - Fix a resource leak

- Detected by cppcheck
tcp: Increase default IW to 4.

This helps ACK loss case and will not cause obvious buffer bloating.

OKed-by: dillon@
inet6: Don't allow setting net.inet6.ip6.v6only to 0
inet6: Only allow setting IPV6_V6ONLY sockopt to 1.
Adjust for the removal of the net.inet6.ip6.v6only sysctl.