Move if_smc_fdt.c to live in sys/dev/smc. It's not specific to the ARM
Versatile hardware.
o Add sysctls to enable/disable potentially dengerous key combinations, like
        reboot/halt/debug.
o Add support for most key combinations supported by syscons(4).

Reviewed by:	dumbbell, emaste (prev revision of D747)
MFC after:	5 days
Sponsored by:	The FreeBSD Foundation
spelling fixes

Submitted by:	"Sam Fourman Jr." <sfourman@gmail.com>
MFC after:	1 week
Fix one more spelling mistake.

Pointed by:	danfe
Introduce INP6_PCBHASHKEY macro. Replace usage of hardcoded part of
IPv6 address as hash key in all places.

Obtained from:	Yandex LLC
Remove unused arguments for VOP_GETPAGES(), VOP_PUTPAGES().
Stop accessing the saved stack pointer by looking past the end of the
array of registers.

Submitted by:	Michal Meloun <meloun at miracle.cz>
Make in6_pcblookup_hash_locked and in6_pcbladdr static.

Obtained from:	Yandex LLC
Sponsored by:	Yandex LLC
Make it possible to disable NOP-In PDUs by the iSCSI initiator by setting
kern.cam.ctl.iscsi.ping_timeout to 0.  This fixes interoperability with
some initiators that don't properly support NOP-Ins, namely iPXE/gPXE.

Submitted by:	Chen Wen <pokkys@gmail.com>
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Add more register values to armreg.h and remove CPU_CONTROL_32BP_ENABLE
from asm.h as they were already defined in armreg.h.

Submitted by:	Michal Meloun <meloun at miracle.cz>
Make sure we handle less than zero timeouts in iSCSI initiator and target
in a reasonable way.

Sponsored by:	The FreeBSD Foundation
Add additional checks for IPV6_PKTINFO handling (RFC 3542):

* Return ENETDOWN when interface specified by ipi6_ifindex is not
  enabled for IPv6 use.
* Return EADDRNOTAVAIL when ipi6_ifindex specifies an interface, but the
  address ipi6_addr is not available for use on that interface.
* Return EINVAL when ipi6_addr is multicast address.

Obtained from:	Yandex LLC
Sponsored by:	Yandex LLC
Abort the create_socket test if socket creation fails.

MFC after:	1 week
Reported by:	Coverity
CID:		1232756
Unify interrupts bit definition and usage. While here remove PSR_C_bit.

Submitted by:	Svatopluk Kraus <onwahe at gmail.com>,
		Michal Meloun <meloun at miracle.cz>
Differential Revision: https://reviews.freebsd.org/D754