meta/classes/qemu.bbclass: set -cpu of ppce5500/ppce6500 to e500mc
The e5500 and e6500 cpu types are not supported by native qemu, set the value
of -cpu to e500mc. Without this change, build will fail for packages which use
qemuwrapper in compile phase due to the following error.
| Unable to find CPU definition
e.g. gobject-introspection
Signed-off-by: Zhenhua Luo <zhenhua.luo@nxp.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
