Fix idle=poll

From hugh@veritas.com 

x86_64 idle=poll might be a little less responsive than it should: unlike
mwait_idle, and unlike i386, its poll_idle left TIF_POLLING_NRFLAG set.

Signed-off-by: Hugh Dickins <hugh@veritas.com>

--- 2.6.13-rc7/arch/x86_64/kernel/process.c	2005-08-24 11:13:06.000000000 +0100
+++ linux/arch/x86_64/kernel/process.c	2005-08-25 17:11:52.000000000 +0100
@@ -123,6 +123,7 @@ static void poll_idle (void)
 			: :
 			"i" (_TIF_NEED_RESCHED), 
 			"m" (current_thread_info()->flags));
+		clear_thread_flag(TIF_POLLING_NRFLAG);
 	} else {
 		set_need_resched();
 	}