MIPS: Octeon: Fix broken EDAC driver.

Commit "MIPS: Octeon: Remove unused L2C types and macros." broke the
the EDAC driver. Bring back 'cvmx-l2d-defs.h' file and the missing
types for L2C. Fixes: 15f68479 ("MIPS: Octeon: Remove unused L2C
types and macros.")

Fixes: 15f68479 ("MIPS: Octeon: Remove unused L2C types and macros.")
Signed-off-by: Steven J. Hill <steven.hill@cavium.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 4.12+
Patchwork: https://patchwork.linux-mips.org/patch/16906/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>