FMC: NULL dereference on allocation failure

If we don't allocate "arr" then the cleanup path will dereference it and
oops.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Alessandro Rubini <rubini@gnudd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>