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/helper.c b/target-m68k/helper.c
index 54fa419..dcadfab 100644
--- a/target-m68k/helper.c
+++ b/target-m68k/helper.c
@@ -290,7 +290,7 @@
 /* MMU */
 
 /* TODO: This will need fixing once the MMU is implemented.  */
-hwaddr cpu_get_phys_page_debug(CPUM68KState *env, target_ulong addr)
+hwaddr m68k_cpu_get_phys_page_debug(CPUState *cs, vaddr addr)
 {
     return addr;
 }