SMAP AMD64: added stac() and clac() to cpufunc.h

Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com>
SMAP AMD64: added CR4_SMAP to sys/x86/include/specialreg.h

Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com>
SMAP AMD64: updated PSL_AC's comment in sys/x86/include/psl.h

Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com>
SMAP AMD64: disable SMAP when running in hypervisor (like SMEP)

Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com>
SMAP AMD64: postpone enabling of SMAP, same like in SMEP case

Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com>
SMAP AMD64: added related trap handler

Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com>
SMAP AMD64: enable SMAP at boot time

Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com>