After all the previous patches, spliting the bitmap gets direct.
Note: For some reason, I have to move DIRTY_MEMORY_* definitions to
the beginning of memory.h to make compilation work.
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Orit Wasserman <owasserm@redhat.com>