As a follow-up to r339930 and various reports implement logging in case
we fail during module load because the pcpu or vnet module sections are
full. We did return a proper error but not leaving any indication to
the user as to what the actual problem was.

Even worse, on 12/13 currently we are seeing an unrelated error (ENOSYS
instead of ENOSPC, which gets skipped over in kern_linker.c) to be
printed which made problem diagnostics even harder.

PR: 228854
MFC after: 3 days