SMAP AMD64: trim whitespaces in amd64/support.S

Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com>
SMAP AMD64: added stac and clac to funtions which live in support.S and interacted with user-space

Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com>
SMAP AMD64: clear SMAP state in NMI handler, as soon as possible

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