target-arm: A64: add set_pc cpu method When executing translation blocks we need to be able to recover our program counter. Add a method to set it for AArch64 CPUs. This covers user-mode, but for system mode emulation we will need to check if the CPU is in an AArch32 execution state. Signed-off-by: Alexander Graf <agraf@suse.de> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <rth@twiddle.net>