hpfs: kstrdup() out of memory handling

There is a possibility of nothing being allocated to the new_opts in
case of memory pressure, therefore return ENOMEM for such case.

Signed-off-by: Sanidhya Kashyap <sanidhya.gatech@gmail.com>
Signed-off-by: Mikulas Patocka <mikulas@twibright.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>