scripts/runqemu-internal: use -cpu core2duo for qemux86-64

scripts/runqemu-internal: use -cpu core2duo for qemux86-64

Now that the tune for qemux86-64 changed to core2-64 we need to
tell the emulator to use a proper CPU model. With the default setting
of qemu64 we'll get things like:

root@qemux86-64:~# smart --help
traps: python[758] trap invalid opcode ip:7f2af01f6be7 sp:7fff49466ef0 error:0 in strop.so[7f2af01f5000+6000]
Illegal instruction

If the tune for qemux86 changes, that needs to be updated too.

(From OE-Core rev: e6ade33a6f52434e884dd97549b8ac731347d9ad)

Signed-off-by: Stefan Stanacar <stefanx.stanacar@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>