In sys/arm/versatile/versatile_pci.c, add a default handler, to fix a
gcc warning about uninitialized use of a variable.

Approved by:	re (gjb)
Sanitize the %eflags returned by BIOS routines.  Some BIOS routines enter
protected mode and may leave protected-mode-specific flags like PSL_NT set
when they return to real mode.  This can cause a fault when BTX re-enters
protected mode after the BIOS mode returns.

PR:		amd64/182740
Reported by:	Julian Pidancet <julian.pidancet@gmail.com>
Approved by:	re (gjb)
MFC after:	1 week
Fix the "am I a net80211 vap" check for bpf listeners.

I changed it to use if_transmit a while ago but apparently with monitor
mode the if_transmit method is overridden.

This is (mostly) a workaround until a more permanent solution can be
found.

Submitted by:	Patrick Kelsey <kelsey@ieee.org>
Approved by:	re@ (gjb)