dmaengine: dw-edma: Add spinlock to protect DONE_INT_MASK and ABORT_INT_MASK

dmaengine: dw-edma: Add spinlock to protect DONE_INT_MASK and ABORT_INT_MASK

The DONE_INT_MASK and ABORT_INT_MASK registers are shared by all DMA
channels, and modifying them requires a read-modify-write sequence.
Because this operation is not atomic, concurrent calls to
dw_edma_v0_core_start() can introduce race conditions if two channels
update these registers simultaneously.

Add a spinlock to serialize access to these registers and prevent race
conditions.

Fixes: 7e4b8a4fbe2c ("dmaengine: Add Synopsys eDMA IP version 0 support")
Cc: stable@vger.kernel.org
Signed-off-by: Frank Li <Frank.Li@nxp.com>
[den: update dw_edma.lock comment]
Link: https://lore.kernel.org/dmaengine/20260109-edma_ll-v2-1-5c0b27b2c664@nxp.com/
Signed-off-by: Koichiro Den <den@valinux.co.jp>
Link: https://patch.msgid.link/20260521142153.2957432-5-den@valinux.co.jp
Signed-off-by: Vinod Koul <vkoul@kernel.org>