haven: dbl: Fix use-after-free in tx/rx unregister

The hh_dbl_tx_unregister() and hh_dbl_rx_unregister() functions
tries to dereference client_desc in pr_debug(), which would
have already been freed if the tx/rx's counterpart was unregistered.
Hence, move the pr_debug() statements right before the section
where kfree() is called on client_desc to avoid use-after-free.

Change-Id: I183b0a3df0665ab90a85e0907b39641cd19f4923
Signed-off-by: Raghavendra Rao Ananta <rananta@codeaurora.org>