xtensa: provide DMA_ERROR_CODE definition

This fixes the following allmodconfig build error:

drivers/uio/uio_dmem_genirq.c:95:18: error: 'DMA_ERROR_CODE' undeclared (first use in this function)
drivers/uio/uio_dmem_genirq.c:238:18: error: 'DMA_ERROR_CODE' undeclared (first use in this function)
make[3]: *** [drivers/uio/uio_dmem_genirq.o] Error 1

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

arch/xtensa/include/asm/dma-mapping.h

@@ -16,6 +16,8 @@
 #include <linux/mm.h>
 #include <linux/scatterlist.h>
 
+#define DMA_ERROR_CODE		(~(dma_addr_t)0x0)
+
 /*
  * DMA-consistent mapping functions.
  */