can: CAN_MCP251X should depend on HAS_DMA

When building for Sun 3:

drivers/net/can/mcp251x.c:1074: undefined reference to `dma_free_coherent'
drivers/net/can/mcp251x.c:976: undefined reference to `dma_alloc_coherent'
drivers/net/can/mcp251x.c:1050: undefined reference to `dma_free_coherent'
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/can/Kconfig

@@ -50,7 +50,7 @@ config CAN_TI_HECC
 
 config CAN_MCP251X
 	tristate "Microchip MCP251x SPI CAN controllers"
-	depends on CAN_DEV && SPI
+	depends on CAN_DEV && SPI && HAS_DMA
 	---help---
 	  Driver for the Microchip MCP251x SPI CAN controllers.