wcn36xx: Release DMA channel descriptor allocations

wcn36xx: Release DMA channel descriptor allocations

BugLink: https://bugs.launchpad.net/bugs/1959376
[ Upstream commit 3652096e5263ad67604b0323f71d133485f410e5 ]

When unloading the driver we are not releasing the DMA descriptors which we
previously allocated.

Fixes: 8e84c2582169 ("wcn36xx: mac80211 driver for Qualcomm WCN3660/WCN3680 hardware")
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211105122152.1580542-3-bryan.odonoghue@linaro.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>