rocker: fix incorrect error handling in dma_rings_init

In rocker_dma_rings_init, the goto blocks in case of errors
caused by the functions rocker_dma_cmd_ring_waits_alloc() and
rocker_dma_ring_create() are incorrect. The patch fixes the
order consistent with cleanup in rocker_dma_rings_fini().

Signed-off-by: Aditya Pakki <pakki001@umn.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>