Fix autofs compile without CONFIG_COMPAT

commit 3c761ea0 upstream.

The autofs compat handling fix caused a compile failure when
CONFIG_COMPAT isn't defined.

Instead of adding random #ifdef'fery in autofs, let's just make the
compat helpers earlier to use: without CONFIG_COMPAT, is_compat_task()
just hardcodes to zero.

We could probably do something similar for a number of other cases where
we have #ifdef's in code, but this is the low-hanging fruit.
Reported-and-tested-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/compat.h

@@ -311,5 +311,9 @@ asmlinkage long compat_sys_openat(unsigned int dfd, const char __user *filename,
 
 extern void __user *compat_alloc_user_space(unsigned long len);
 
+#else
+
+#define is_compat_task() (0)
+
 #endif /* CONFIG_COMPAT */
 #endif /* _LINUX_COMPAT_H */