hw/ppc/spapr_hcall: Rename {softmmu -> vhyp_mmu}_resize_hpt_pr

hw/ppc/spapr_hcall: Rename {softmmu -> vhyp_mmu}_resize_hpt_pr

Since 'softmmu' is quite a loaded term in QEMU, rename the vhyp MMU
facilities to use the vhyp_mmu_ prefix rather than softmmu_.

vhyp_mmu_ is chosen because the code that manipulates the hash table
via guest software hypercalls is QEMU's implementation of the PAPR
hypervisor interface, called vhyp.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
[npiggin: Pick a different name, explain it in changelog.]
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>