xfs: Use kmem_free() instead of free()

This fixes a build failure caused by calling the free() function which
does not exist in the Linux kernel.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

(cherry picked from commit aaaae980)

fs/xfs/xfs_log_recover.c

@@ -1585,7 +1585,7 @@ xlog_recover_add_to_trans(
 		"bad number of regions (%d) in inode log format",
 				  in_f->ilf_size);
 			ASSERT(0);
-			free(ptr);
+			kmem_free(ptr);
 			return XFS_ERROR(EIO);
 		}