Use stub bfd for dynobj

[Andreas Schwab]

It broke the 843419 errata fixup:

  41507c:       d0001be1        adrp    x1, 793000 <ptroot+0x10>
  415080:       f943e422        ldr     x2, [x1, #1992]
  415084:       d0001be1        adrp    x1, 793000 <ptroot+0x10>
  415088:       1400baf8        b       443c68 <e843419@0008_00000037_106e8>
  41508c:       d63f0060        blr     x3


0000000000443c68 <e843419@0008_00000037_106e8>:
  443c68:       00000000        udf     #0
  443c6c:       17ff4508        b       41508c <ldlang_open_output+0x124>

Note that the veneered insn in the stub is left unset.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
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