atomic: use <linux/atomic.h>

This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>

Signed-off-by: Arun Sharma <asharma@fb.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/md/dm-queue-length.c b/drivers/md/dm-queue-length.c
index f92b6ce..03a837a 100644
--- a/drivers/md/dm-queue-length.c
+++ b/drivers/md/dm-queue-length.c
@@ -20,7 +20,7 @@
 #include <linux/ctype.h>
 #include <linux/errno.h>
 #include <linux/module.h>
-#include <asm/atomic.h>
+#include <linux/atomic.h>
 
 #define DM_MSG_PREFIX	"multipath queue-length"
 #define QL_MIN_IO	128