MIPS: Alchemy: fix dbdma2

stable inclusion
from stable-v5.10.185
commit 619672bf2d04cdc1bc3925defd0312c2ef11e5d0
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8L5XP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=619672bf2d04cdc1bc3925defd0312c2ef11e5d0



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[ Upstream commit 2d645604 ]

Various fixes for the Au1200/Au1550/Au1300 DBDMA2 code:

- skip cache invalidation if chip has working coherency circuitry.
- invalidate KSEG0-portion of the (physical) data address.
- force the dma channel doorbell write out to bus immediately with
  a sync.

Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>