timer_list: Remove alignment padding on 64 bit when CONFIG_TIMER_STATS

Reorder struct timer_list to remove 8 bytes of alignment padding on 64
bit builds when CONFIG_TIMER_STATS is selected.

timer_list is widely used across the kernel so many structures will
benefit and shrink in size.

For example, with my config on x86_64
	per_cpu_dm_data shrinks from 136 to 128 bytes
and
	ahci_port_priv shrinks from 1032 to 968 bytes.
Signed-off-by: NRichard Kennedy <richard@rsk.demon.co.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

include/linux/timer.h

@@ -24,9 +24,9 @@ struct timer_list {
 	int slack;
 
 #ifdef CONFIG_TIMER_STATS
+	int start_pid;
 	void *start_site;
 	char start_comm[16];
-	int start_pid;
 #endif
 #ifdef CONFIG_LOCKDEP
 	struct lockdep_map lockdep_map;