Add book3s_64 specific opcode emulation

There are generic parts of PowerPC that can be shared across all
implementations and specific parts that only apply to BookE or desktop PPCs.

This patch adds emulation for desktop specific opcodes that don't apply
to BookE CPUs.

Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>