cpu: Directly use get_paging_enabled() fallback handlers in place

No code uses CPUClass::get_paging_enabled() outside of hw/core/cpu.c:

  $ git grep -F -- '->get_paging_enabled'
  hw/core/cpu.c:74:    return cc->get_paging_enabled(cpu);
  hw/core/cpu.c:438:    k->get_paging_enabled = cpu_common_get_paging_enabled;
  target/i386/cpu.c:7418:    cc->get_paging_enabled = x86_cpu_get_paging_enabled;

Check the handler presence in place and remove the common fallback code.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210517105140.1062037-10-f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

hw/core/cpu-common.c

@@ -66,18 +66,6 @@ CPUState *cpu_create(const char *typename)
     return cpu;
 }
 
-bool cpu_paging_enabled(const CPUState *cpu)
-{
-    CPUClass *cc = CPU_GET_CLASS(cpu);
-
-    return cc->get_paging_enabled(cpu);
-}
-
-static bool cpu_common_get_paging_enabled(const CPUState *cpu)
-{
-    return false;
-}
-
 void cpu_get_memory_mapping(CPUState *cpu, MemoryMappingList *list,
                             Error **errp)
 {
@@ -316,7 +304,6 @@ static void cpu_class_init(ObjectClass *klass, void *data)
     k->parse_features = cpu_common_parse_features;
     k->get_arch_id = cpu_common_get_arch_id;
     k->has_work = cpu_common_has_work;
-    k->get_paging_enabled = cpu_common_get_paging_enabled;
     k->get_memory_mapping = cpu_common_get_memory_mapping;
     k->gdb_read_register = cpu_common_gdb_read_register;
     k->gdb_write_register = cpu_common_gdb_write_register;

hw/core/cpu-sysemu.c

@@ -22,6 +22,17 @@
 #include "qapi/error.h"
 #include "hw/core/cpu.h"
 
+bool cpu_paging_enabled(const CPUState *cpu)
+{
+    CPUClass *cc = CPU_GET_CLASS(cpu);
+
+    if (cc->get_paging_enabled) {
+        return cc->get_paging_enabled(cpu);
+    }
+
+    return false;
+}
+
 hwaddr cpu_get_phys_page_attrs_debug(CPUState *cpu, vaddr addr,
                                      MemTxAttrs *attrs)
 {