compat: remove compat_printk()

After 7e8e385aaf ("x86/compat: Remove sys32_vm86_warning"), this
function has become unused, so we can remove it as well.

Link: http://lkml.kernel.org/r/20160617142903.3070388-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/compat.c

@@ -54,20 +54,6 @@
 #include <asm/ioctls.h>
 #include "internal.h"
 
-int compat_log = 1;
-
-int compat_printk(const char *fmt, ...)
-{
-	va_list ap;
-	int ret;
-	if (!compat_log)
-		return 0;
-	va_start(ap, fmt);
-	ret = vprintk(fmt, ap);
-	va_end(ap);
-	return ret;
-}
-
 /*
  * Not all architectures have sys_utime, so implement this in terms
  * of sys_utimes.