wifi: mt76: dma: free rx_head in mt76_dma_rx_cleanup

stable inclusion
from stable-v5.10.173
commit 46ce77b07cd83b12cbe6f1aa617cf4487b06317a
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8BFR3

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=46ce77b07cd83b12cbe6f1aa617cf4487b06317a



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[ Upstream commit 1b88b47e ]

Free rx_head skb in mt76_dma_rx_cleanup routine in order to avoid
possible memory leak at module unload.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>