PAX ASLR: added vm == NULL check to _pax_aslr_init{,32} functions

Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com>
PAX ASLR: change hard-coded function name to __func__ in panic messages

Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com>
PAX ASLR: apply style(9) - indent

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