target/arm/kvm64: Move the get/put of fpsimd registers out
Move the getting/putting of the fpsimd registers out of
kvm_arch_get/put_registers() into their own helper functions
to prepare for alternatively getting/putting SVE registers.
No functional change.
Signed-off-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>