crypto: safexcel - Add error handling for dma_map_sg() calls

In the Linux kernel, the following vulnerability has been resolved: crypto: safexcel - Add error handling for dma_map_sg() calls Macro dma_map_sg() may return 0 on error. This patch enables checks in case of the macro failure and ensures unmapping of previously mapped buffers with dma_unmap_sg(). Found by Linux Verification Center (linuxtesting.org) with static analysis tool SVACE.