Make the mips64r6 config pretend it has a 2nd arch

This fix buildbot's mips64 build. This is the same solution
as it is done in I5372c6a1d2e1e2462ef8671eef3a2337517ec0c8.

Change-Id: Ibe12cf7fbd9fc15a08ba984cf086302f175525f7
1 file changed
tree: 4b1f70a1bc60c443b0d8f22f6fc51f6db3e666f0
  1. arm_krait/
  2. armv8/
  3. mips32r2_fp/
  4. mips32r2_fp_xburst/
  5. mips64r6/
  6. silvermont/