tcg-mips: Add mips64 opcodes

Since the mips manual tables are in octal, reorg all of the opcodes
into that format for clarity.  Note that the 64-bit opcodes are as
yet unused.

Tested-by: Aurelien Jarno <aurelien@aurel32.net>
Tested-by: James Hogan <james.hogan@imgtec.com>
Tested-by: YunQiang Su <wzssyqa@gmail.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Jin Guojie <jinguojie@loongson.cn>
Message-Id: <1483592275-4496-3-git-send-email-jinguojie@loongson.cn>