dmaengine: mv_xor: Fix missing check after DMA map and missing unmap

dmaengine: mv_xor: Fix missing check after DMA map and missing unmap

[ Upstream commit 60095aca6b471b7b7a79c80b7395f7e4e414b479 ]

The DMA map functions can fail and should be tested for errors.

In case of error, unmap the already mapped regions.

Fixes: 22843545b200 ("dma: mv_xor: Add support for DMA_INTERRUPT")
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
Link: https://lore.kernel.org/r/20250701123753.46935-2-fourier.thomas@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>