lib/vsprintf.c: remove %Z support

Now that %z is standartised in C99 there is no reason to support %Z.
Unlike %L it doesn't even make format strings smaller.

Use BUILD_BUG_ON in a couple ATM drivers.

In case anyone didn't notice lib/vsprintf.o is about half of SLUB which
is in my opinion is quite an achievement.  Hopefully this patch inspires
someone else to trim vsprintf.c more.

Link: http://lkml.kernel.org/r/20170103230126.GA30170@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/net/ieee802154/socket.c b/net/ieee802154/socket.c
index e0bd013..eedba76 100644
--- a/net/ieee802154/socket.c
+++ b/net/ieee802154/socket.c
@@ -279,7 +279,7 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 	pr_debug("name = %s, mtu = %u\n", dev->name, mtu);
 
 	if (size > mtu) {
-		pr_debug("size = %Zu, mtu = %u\n", size, mtu);
+		pr_debug("size = %zu, mtu = %u\n", size, mtu);
 		err = -EMSGSIZE;
 		goto out_dev;
 	}
@@ -645,7 +645,7 @@ static int dgram_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 	pr_debug("name = %s, mtu = %u\n", dev->name, mtu);
 
 	if (size > mtu) {
-		pr_debug("size = %Zu, mtu = %u\n", size, mtu);
+		pr_debug("size = %zu, mtu = %u\n", size, mtu);
 		err = -EMSGSIZE;
 		goto out_dev;
 	}