cpu: Turn cpu_get_phys_page_debug() into a CPUClass hook

Change breakpoint_invalidate() argument to CPUState alongside.

Since all targets now assign a softmmu-only field, we can drop helpers
cpu_class_set_{do_unassigned_access,vmsd}() and device_class_set_vmsd().

Prepares for changing cpu_memory_rw_debug() argument to CPUState.

Acked-by: Max Filippov <jcmvbkbc@gmail.com> (for xtensa)
Signed-off-by: Andreas Färber <afaerber@suse.de>
diff --git a/target-m68k/cpu.c b/target-m68k/cpu.c
index 43011e7..988f476 100644
--- a/target-m68k/cpu.c
+++ b/target-m68k/cpu.c
@@ -190,6 +190,9 @@
     cc->do_interrupt = m68k_cpu_do_interrupt;
     cc->dump_state = m68k_cpu_dump_state;
     cc->set_pc = m68k_cpu_set_pc;
+#ifndef CONFIG_USER_ONLY
+    cc->get_phys_page_debug = m68k_cpu_get_phys_page_debug;
+#endif
     dc->vmsd = &vmstate_m68k_cpu;
 }