dmaengine: bcm-sba-raid: fix device leak on probe

dmaengine: bcm-sba-raid: fix device leak on probe

commit 7c3a46ebf15a9796b763a54272407fdbf945bed8 upstream.

Make sure to drop the reference taken when looking up the mailbox device
during probe on probe failures and on driver unbind.

Fixes: 743e1c8ffe4e ("dmaengine: Add Broadcom SBA RAID driver")
Cc: stable@vger.kernel.org	# 4.13
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20251117161258.10679-4-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>