Fix undefined behaviour in several gpio_pin_setflags() routines (under
sys/arm and sys/mips), squelching the clang 3.3 warnings about this.

Noticed by:	tinderbox and many irate spectators
Submitted by:	Luiz Otavio O Souza <loos.br@gmail.com>
PR:		kern/177759
MFC after:	3 days
Create sysctl node 'hw.vmm.vmx' and populate it with oids that expose the VMX
hardware capabilities.

Obtained from:	NetApp