When an urb buffer can't be allocated, the currently allocated
buffer count must be saved so they can properly released.
Moreover, it's sufficient to call stk1160_free_isoc to have
all urb buffers released.
Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>