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>

sound/pci/pcxhr/pcxhr_hwdep.c

@@ -292,7 +292,7 @@ static int pcxhr_dsp_load(struct pcxhr_mgr *mgr, int index,
 	int err, card_index;
 
 	dev_dbg(&mgr->pci->dev,
-		"loading dsp [%d] size = %Zd\n", index, dsp->size);
+		"loading dsp [%d] size = %zd\n", index, dsp->size);
 
 	switch (index) {
 	case PCXHR_FIRMWARE_XLX_INT_INDEX: