Do not set preload_addr_relocate for ARM. Apparently there was a time

Do not set preload_addr_relocate for ARM.  Apparently there was a time
when loader(8) passed physical addresses in loader metadata for arm, but
that is no longer true; all metadata has already been adjusted to vitual
addresses by loader.

I can't track down the exact revision in loader where a change from physical
to virtual metadata addresses happened.  The code involved is very twisty
and complicated.  I suspect the change was an unintended consequence of the
r247301, r247413, r248118 series of changes I made a couple years ago.