adding gprh registers to store GPR MSBs when GPRs are 32 bits.
Remove not-needed-anymore ppcemb-linux-user target.
Keep ppcemb-softmmu target, which provides 1kB pages support
  and 36 bits physical address space.


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3628 c046a42c-6fe2-441c-8c8c-71466251a162