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/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index d8cea21..2f0d823 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -2388,7 +2388,7 @@
 
 	seq_printf(seq,
 		   "Basic info: size of leaf:"
-		   " %Zd bytes, size of tnode: %Zd bytes.\n",
+		   " %zd bytes, size of tnode: %zd bytes.\n",
 		   LEAF_SIZE, TNODE_SIZE(0));
 
 	for (h = 0; h < FIB_TABLE_HASHSZ; h++) {