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/mm/dmapool.c b/mm/dmapool.c
index cef82b8..4d90a64 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -93,7 +93,7 @@ show_pools(struct device *dev, struct device_attribute *attr, char *buf)
 		spin_unlock_irq(&pool->lock);
 
 		/* per-pool info, no real statistics yet */
-		temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",
+		temp = scnprintf(next, size, "%-16s %4u %4zu %4zu %2u\n",
 				 pool->name, blocks,
 				 pages * (pool->allocation / pool->size),
 				 pool->size, pages);