exec: Let address_space_unmap() use a boolean 'is_write' argument

The 'is_write' argument is either 0 or 1.
Convert it to a boolean type.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>

exec.c

@@ -3598,11 +3598,11 @@ void *address_space_map(AddressSpace *as,
 }
 
 /* Unmaps a memory region previously mapped by address_space_map().
- * Will also mark the memory as dirty if is_write == 1.  access_len gives
+ * Will also mark the memory as dirty if is_write is true.  access_len gives
  * the amount of memory that was actually read or written by the caller.
  */
 void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len,
-                         int is_write, hwaddr access_len)
+                         bool is_write, hwaddr access_len)
 {
     if (buffer != bounce.buffer) {
         MemoryRegion *mr;

include/exec/memory.h

@@ -2329,7 +2329,7 @@ void *address_space_map(AddressSpace *as, hwaddr addr,
  * @is_write: indicates the transfer direction
  */
 void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len,
-                         int is_write, hwaddr access_len);
+                         bool is_write, hwaddr access_len);
 
 
 /* Internal functions, part of the implementation of address_space_read.  */