stand/common/load_elf: Do kernel module relocations for PPC

[ivy]

Summary

reloc_ptr() skips relocations for the kernel module, because on most
platforms the kernel is ET_EXEC and this is not required. On PPC,
the kernel is ET_DYN and we need to relocate here, otherwise the
module metadata will not be loaded properly and the kernel module
will have an incorrect version, preventing module dependencies from
resolving.

This fixes loading kernel modules from loader.conf on powerpc.

Diagnosed by: jrtc27
Sponsored by: https://www.patreon.com/bsdivy

[adrian]

neat! why's the kernel ET_DYN on ppc anyway?

[jrtc27]

I now understand why this case is there and am contemplating unifying the two paths so this condition can just be deleted even on non-PowerPC (it's more interesting on CHERI where even our ET_EXEC will have relocations for capabilities, but not integer addresses...), but for now this should be sufficient.