memory: s/dirty/clean/ in cpu_physical_memory_is_dirty()

All uses except one really want the other meaning.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Orit Wasserman <owasserm@redhat.com>
diff --git a/exec.c b/exec.c
index 9267596..47add21 100644
--- a/exec.c
+++ b/exec.c
@@ -1514,7 +1514,7 @@
     cpu_physical_memory_set_dirty_flag(ram_addr, DIRTY_MEMORY_VGA);
     /* we remove the notdirty callback only if the code has been
        flushed */
-    if (cpu_physical_memory_is_dirty(ram_addr)) {
+    if (!cpu_physical_memory_is_clean(ram_addr)) {
         CPUArchState *env = current_cpu->env_ptr;
         tlb_set_dirty(env, env->mem_io_vaddr);
     }
@@ -1917,7 +1917,7 @@
 static void invalidate_and_set_dirty(hwaddr addr,
                                      hwaddr length)
 {
-    if (!cpu_physical_memory_is_dirty(addr)) {
+    if (cpu_physical_memory_is_clean(addr)) {
         /* invalidate code */
         tb_invalidate_phys_page_range(addr, addr + length, 0);
         /* set dirty bit */
@@ -2533,7 +2533,7 @@
         stl_p(ptr, val);
 
         if (unlikely(in_migration)) {
-            if (!cpu_physical_memory_is_dirty(addr1)) {
+            if (cpu_physical_memory_is_clean(addr1)) {
                 /* invalidate code */
                 tb_invalidate_phys_page_range(addr1, addr1 + 4, 0);
                 /* set dirty bit */