mailbox: th1520: fix clock imbalance on probe failure

mailbox: th1520: fix clock imbalance on probe failure

The purpose of the devm_add_action_or_reset() helper is to call the
action function in case adding an action ever fails so drop the clock
disable from the error path to avoid disabling the clocks twice.

Fixes: 5d4d263e1c6b ("mailbox: Introduce support for T-head TH1520 Mailbox driver")
Cc: Michal Wilczynski <m.wilczynski@samsung.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Michal Wilczynski <m.wilczynski@samsung.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>