staging/lustre/build: fix compilation issue with is_compat_task

After removing LIBCFS_HAVE_IS_COMPAT_TASK test we have a
compilation issue with kernels configured without CONFIG_COMPAT.

Lustre-change: http://review.whamcloud.com/7118
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-2800Signed-off-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/llite/llite_internal.h

@@ -651,7 +651,12 @@ static inline int ll_need_32bit_api(struct ll_sb_info *sbi)
 #if BITS_PER_LONG == 32
 	return 1;
 #else
-	return unlikely(is_compat_task() || (sbi->ll_flags & LL_SBI_32BIT_API));
+	return unlikely(
+#ifdef CONFIG_COMPAT
+		is_compat_task() ||
+#endif
+		(sbi->ll_flags & LL_SBI_32BIT_API)
+	);
 #endif
 }