[lldb] Try to fix build after d1556e5

Getting lots of `error: unknown type name 'uint64_t'` and `uint32_t`
in this file on Linux.

Author: nico

lldb/include/lldb/Target/RegisterFlags.h

@@ -9,6 +9,7 @@
 #ifndef LLDB_TARGET_REGISTERFLAGS_H
 #define LLDB_TARGET_REGISTERFLAGS_H
 
+#include <stdint.h>
 #include <string>
 #include <vector>