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.

sys/arm/arm/machdep.c

@@ -1019,7 +1019,6 @@ freebsd_parse_boot_param(struct arm_boot_params *abp)
 	ksym_end = MD_FETCH(kmdp, MODINFOMD_ESYM, uintptr_t);
 	db_fetch_ksymtab(ksym_start, ksym_end);
 #endif
-	preload_addr_relocate = KERNVIRTADDR - abp->abp_physaddr;
 	return lastaddr;
 }
 #endif