wlan - use wlan_global_serializer as if serializer

This fixes problems on SMP system using ath(4).

suggested-by: Sepherosa Ziehau <sepherosa@gmail.com>
iwn - don't acquire wlan_global_serializer in iwn_start()

With abc2d9274 iwn_start() is called with wlan_global_serializer
held already.
wlan - wlan_assert_serialized in ieee80211_init/_start/_ioctl
ath - wlan_assert_serialized in ath_init/_start/_ioctl
iwn - wlan_assert_serialized in iwn_init/_start/_ioctl
merge
merge
Merge branch 'master' of git://git.dragonflybsd.org/dragonfly into wlan_serialize
ral: release wlan serializer while loading firmware
Merge branch 'master' of git://git.dragonflybsd.org/dragonfly into wlan_serialize
bge: Limit STD RX ring prod index increment to 8 for 5750, 5752 and 5755

This works around hardware errata.

NOTE:
For 5750, 5752 and 5755, the STD RX ring replesh threshold has already
been set to 8.

Obtained-from: tg3
bnx: Properly setup TX ring prod index position
ciss(4): Fix build with CISS_DEBUG.
Merge remote-tracking branch 'hofmann/wlan_serialize'
bnx: Pack TX mbuf and dmamap together; improve cache utilization
libc: Fix -Wmissing-include-dirs.
bsd.sys.mk: Add -Wmissing-include-dirs to WARNS >= 1.

It ensures that all directories passed with -I<dir> actually exist.
kernel: Make tty_compat.c optional in 'files' instead of in the source.
kernel/mfi: Add a tunable/sysctl to modify the command timeout.
mfi(4)/mfiutil(8): Add support for foreign configurations and drives.

For this, the following commands are added to mfiutil(8):

foreign scan - lists the number of foreign configs
foreign drives - lists the drives which are flagged as foreign
foreign display - displays the specified foreign configuration
foreign preview - previews the specified foreign configuration after import
foreign clear - clears the foreign configuration
foreign import - imports the foreign configuration

Foreign drive support has been added to 'show drives' too.

Tested-by:  ftigeot
Taken-from: http://www.freebsd.org/cgi/query-pr.cgi?pr=172091