tools include: add __aligned_u64 to types.h.

Following patches will introduce linux/bpf.h to a new libbpf library,
which requires definition of __aligned_u64. This patch add it to the
common types.h for tools.

Signed-off-by: Wang Nan <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Alexei Starovoitov <[e-mail]>
Cc: Brendan Gregg <[e-mail]>
Cc: Daniel Borkmann <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Masami Hiramatsu <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: [e-mail]
Cc: Zefan Li <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/include/linux/types.h

···
 	int counter;
 } atomic_t;
 
+#ifndef __aligned_u64
+# define __aligned_u64 __u64 __attribute__((aligned(8)))
+#endif
+
 struct list_head {
 	struct list_head *next, *prev;
 };