Revert "Relax the restriction on what relocations can be in a non-alloc section."

This reverts commit r295102.

In the link of seabios the assumption seems to be that the section has
an actual address, so this is not sufficient. Changing the assembly
code to add a "a" flag seems like the correct thing to do instead of
extending this hack.

Sorry about the noise.

Original message:

    Relax the restriction on what relocations can be in a non-alloc section.

    The main thing that they can't have is relocations that require the
    creation of gots or plt.  For now also accept R_PC.

    Found while linking seabios.

llvm-svn: 295130