KVM: PPC: Reimplement LOAD_FP/STORE_FP instruction mmio emulation with analyse_instr() input

This patch reimplements LOAD_FP/STORE_FP instruction MMIO emulation with
analyse_instr() input. It utilizes the FPCONV/UPDATE properties exported by
analyse_instr() and invokes kvmppc_handle_load(s)/kvmppc_handle_store()
accordingly.

For FP store MMIO emulation, the FP regs need to be flushed firstly so
that the right FP reg vals can be read from vcpu->arch.fpr, which will
be stored into MMIO data.

Suggested-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Simon Guo <wei.guo.simon@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>