xscore: add dma address check

xscore: add dma address check

When "swiotlb buffer is full" error occurs, the DMA allocation
will fail. The data conn and control conn are disconnected. Then
xscore will make error handling. In this error handling, the
unallocated DMA address is unmapped. This will result in the crash.
To avoid crash, the dma address check is added.

Orabug: 27074085

Signed-off-by: Zhu Yanjun <yanjun.zhu@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Dhaval Giani <dhaval.giani@oracle.com>