hw/core: Add CPUClass.get_pc

hw/core: Add CPUClass.get_pc

Populate this new method for all targets.  Always match
the result that would be given by cpu_get_tb_cpu_state,
as we will want these values to correspond in the logs.

Reviewed-by: Taylor Simpson <tsimpson@quicinc.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> (target/sparc)
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
Cc: Eduardo Habkost <eduardo@habkost.net> (supporter:Machine core)
Cc: Marcel Apfelbaum <marcel.apfelbaum@gmail.com> (supporter:Machine core)
Cc: "Philippe Mathieu-Daudé" <f4bug@amsat.org> (reviewer:Machine core)
Cc: Yanan Wang <wangyanan55@huawei.com> (reviewer:Machine core)
Cc: Michael Rolnik <mrolnik@gmail.com> (maintainer:AVR TCG CPUs)
Cc: "Edgar E. Iglesias" <edgar.iglesias@gmail.com> (maintainer:CRIS TCG CPUs)
Cc: Taylor Simpson <tsimpson@quicinc.com> (supporter:Hexagon TCG CPUs)
Cc: Song Gao <gaosong@loongson.cn> (maintainer:LoongArch TCG CPUs)
Cc: Xiaojuan Yang <yangxiaojuan@loongson.cn> (maintainer:LoongArch TCG CPUs)
Cc: Laurent Vivier <laurent@vivier.eu> (maintainer:M68K TCG CPUs)
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> (reviewer:MIPS TCG CPUs)
Cc: Aleksandar Rikalo <aleksandar.rikalo@syrmia.com> (reviewer:MIPS TCG CPUs)
Cc: Chris Wulff <crwulff@gmail.com> (maintainer:NiosII TCG CPUs)
Cc: Marek Vasut <marex@denx.de> (maintainer:NiosII TCG CPUs)
Cc: Stafford Horne <shorne@gmail.com> (odd fixer:OpenRISC TCG CPUs)
Cc: Yoshinori Sato <ysato@users.sourceforge.jp> (reviewer:RENESAS RX CPUs)
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> (maintainer:SPARC TCG CPUs)
Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de> (maintainer:TriCore TCG CPUs)
Cc: Max Filippov <jcmvbkbc@gmail.com> (maintainer:Xtensa TCG CPUs)
Cc: qemu-arm@nongnu.org (open list:ARM TCG CPUs)
Cc: qemu-ppc@nongnu.org (open list:PowerPC TCG CPUs)
Cc: qemu-riscv@nongnu.org (open list:RISC-V TCG CPUs)
Cc: qemu-s390x@nongnu.org (open list:S390 TCG CPUs)