metadata load files were consolidated in r329190, and these relocation fixup
bits were inadvertently dropped in the process. Re-add them to fix boot with
ubldr.
Glanced over by: jhibbits
X-MFC-With: r329190
Summary:
All metadata.c files are very similar, with only trivial changes. Unify them
into a single common file, with minor special-casing where needed.
Reviewed By: imp
Differential Revision: https://reviews.freebsd.org/D13978