x32: fix struct statfs

the omission of the padding was uncovered by the latest regression
statvfs regression test added to libc-test.

arch/x32/bits/statfs.h

 struct statfs {
-	unsigned long f_type, f_bsize;
+	unsigned long f_type, __pad0, f_bsize, __pad1;
 	fsblkcnt_t f_blocks, f_bfree, f_bavail;
 	fsfilcnt_t f_files, f_ffree;
 	fsid_t f_fsid;
-	unsigned long f_namelen, f_frsize, f_flags, f_spare[4];
+	unsigned long f_namelen, __pad2, f_frsize, __pad3;
+	unsigned long f_flags, __pad4;
+	unsigned long long f_spare[4];
 };